So, I went ahead and Worked out something for Arche. She does not fly as such but can mimic it pretty well.
Weight: Just under Mario's.
Movement Speed: Similar to the Ice Climbers'.
Air Movement Speed: Similar to Kirby's (not that great but not terrible)
Fall Speed (Normal): Just under Mario's.
Fall Speed (Riding): About that of an umbrella using Peach.
Stance Shift: Arche walks holding her broom in one hand, riding it across the ground for her dash or mounting it mid air for her first jump. Both of these actions put her into her "riding stance", during which she is far floatier but also has far less ability to cancel momentum than any other character. Hitting a wall with or managing to end the dash (except via jumping) will return her to "carry stance", as will touching down on her feet or getting up from the downed position.
Second Jump: Volt appears and gives the broom an upwards boost.
Move List
Specials:
Up B - Tractor Beam: Arche motions, creating a glyph about 2 Arche heights above her head and roughly 5-6 broomless Arches wide. Small particles, seemingly comprised of light, flow upwards to this glyph, carrying anyone caught in the beam along with them. Players will travel upwards at their own fall speed, making this rather ineffective as a 3rd jump but, since they still have sideways control, it may be useful for positioning, or saving teammates in doubles. Players who leave the light will enter a helpless fall state, as will anyone caught in it when it ends. They will then fall at ~2 times the normal speed and, unless they are the user of the move, take damage based on this fall speed when they hit ground.
Neutral B - Thunder Blade: An arc of lightning emanates from a point just above Arche's feet, inside her body. It starts off pointing directly upwards and about 0.6 Arches tall, making it entirely sealed within her body. It rotates through 360 degrees, or until it hits a solid object (excludes players and most items), growing all the time and reaching ~2 Arche heights by the end. Arche falls slightly slower but cannot move in any other way while this is active. If it makes a move ending collision, she will be stunned for half the time the move would otherwise have continued for.
Forward B - Storm: Arche calls forth a blast of air from off screen behind her. Soon after activation, it will collide with her and fire her forward, damaging anyone she hits. Should someone be between her and the source, however, they will receive this windbox instead, though not the damaging properties. Either way, she will have a small helpless time after it ends but it could still potentially be used to pull opponents of stage for vicious followups.
Down B - Meteor Swarm: Arche raises her hand and a large meteor comes in from off screen at a 45 degree angle. It will be aligned to just graze her index finger in passing and, unless hit, she cannot move until this moment has occurred. Since it travels fairly slowly, it is usually easily dealt with, though hitting her out of the move is risky since it positions you in the projectile's path. Do not corner her on a walk off edge though or you're in real trouble! It will easily break shields and cannot be reflected. The side it will come in from is whichever Arche is closest to and is not determined by the way she is facing.
Smashes:
Up Smash - Fire Wall: Arche makes some elaborate gestures, then raises her hands to the sky, with her palms spread and her broom floating (vertical) infront of her. Her hands do a tiny a mount of damage and, if hit, opponents will be pushed sideways slightly, potentially making the main part of the attack miss. Next, a jet of traditionally textured lava about 0.5 broomless Arches in width bursts forth from her palms, climbing all the way to the upper blast zone with a speed based on the length of its charge. Collisions with it act like a weaker version of Brinstar's acid. It lasts a while, though it will end immediately if Arche herself is hit.
Forward Smash - Earthquake: A simple move in which Arche calls forth a series of stalagmites to jut from the ground in a short line infront of her, with the exact number based on the charge time. Yes, this is actually Ground Dasher but Arche doesn't actually have that.
Down Smash - Distortion: Now this is a weird move. Arche slams her broom into the ground (tiny hitbox with some damage) and a burst of temporal energy erupts from that point, resembling that seen in Cless' "Distortion Blade" but actually acting more like Dhaos/Sekundes Corridor. A massive wind will effect all outside the main blast, making this a good "get away from me!" move, its strength will depend on the charge length, with it doing almost nothing at no charge. The blast itself, however, does not effect enemy movement at all. It will stay up for a while and, since its damage over time affect will not impede enemy approach (those inside take small 1-2% hits quite frequently but not the stun or flinch that would normally accompany them), this makes Arche rather vulnerable if she doesn't get that charge time.
Tilts:
Up A - Fire Ball: Arche shoots a fireball upwards and it goes about 0.5 times her height before falling back down and splatting over an invisible shield around her (this bit is just a visual effect). Does no real knockback.
Forward A - Ice Arrow: Arche leans forward and a small icicle forms above her head, flinging itself down at an angle of about 35 degrees from horizontal. Creates a useful little stun but little damage or knockback.
Down A - Grave: Arche makes a motion with her hands as if calling something up from the ground and, low and behold, a stalagmite pokes at her foe.
Aerials:
Up Air - Ray: Arche raises a ball of light above her head which gives off short distance rays. Does little damage and no knockback but "blinds" foes, preventing input registration for a tiny period.
Neutral Air - Explode: Arche motions frantically and then suddenly gives off an explosion. The range is pitiful and the afterlag is terrible too but the damage and knockback are both high.
Forward Air - Flare Tornado: Arche twirls forwards on her broom, generating a small fiery whirlwind around herself. Does damage and does not have a wind effect.
Backward Air - Ice Tornado: Arche twirls backwards on her broom, generating a small icy whirlwind around herself. Does damage and does not have a wind effect.
Down Air - Lightning: A faintly visible transparent image of Volt appears over Arche as she brings her hands together infront of her, then a bolt of lightning travels downward from her broom with an effect much like Pikachu's.
Others:
Neutral Combo - Tetra Spell 1: Arche throws a fireball upwards and slightly forward, causing it to fall down infront of her and damage the opponent slightly.
Neutral Combo - Tetra Spell 2: Activatable any time between the throwing and the collision of the fireball. Arche raises her hand and a tiny lightning bolt strikes from just above her head height down to the point where the fireball would have landed (does not stop the motion of the fireball).
Neutral Combo - Tetra Spell 3: Activatable while the lightning bolt is fading away, Arche strikes the ground and an tiny icicle and stalagmite both jut from the ground at 45 degrees, converging on a point just above the lightning struck ground. Ends the combo.
Dash Attack - Tidal Wave: Water rises from below Arche and, just as she starts to get wet, she comes to an abrupt holt, the front end of her broom jammed into the ground and the back pivoting up into the air. During this motion, the water stays beneath the broom, meaning that, as the back of it rises, a massive wave forms behind her, arcing overhead and crashing down infront of Arche as she returns to a standing position. After this, she pulls her broom from between her legs and returns to her "carry" stance, all momentum gone. Does large damage but has wave properties instead of standard knockback.