If we consider his specials's moveset like this :
B : Axe. He throws it in a arc like in every Castlevania game.
B Side : Holy Crucifix. He can either throw it without it coming back (like in Order Of Shadows) or bringing it back by holding the button.
B Up : Vampire Killer Special Attack (from Portrait Of Ruin but here, it'll be toward the ledge ofc) that can help Simon to grab the ledge from a good distance.
B Down : Holy Water. Explodes and fires an area by dealing damages like Ness's PK Fire but the flames are tinier and cover a large zone.
Final Smash : Item Crush. And you see what I mean. Depends on the last object used.
If Axe :
https://youtu.be/NmNYEmfv92o?t=6
Like this, but at the start, axes will go in front of Simon like it does at the beginning of here, Richter's item crush, but further, and then, they'll go back to Simon, bringing the fighters, and they'll almost explode by going very fast and pushing the fighters at the four corners of the stage, something like this.
If Holy Water : A really beautiful rain of holy water is summoned on the stage and could maybe end with a lighting strike form heavens ?
If Holy Crucifix : Grand Cross. Of COURSE. Deals the best amount of damage among the others final Smashes, as with the Vampire Killer Final Smash.
And what about it, you may ask ?
Simon's whip becomes deadlier and now deals damage in a better range.
I thought of it like that :
At each hit, the whip could change elements like it does in circle of the moon.
Jab : Fire. He deals a punch, then a kick, and a whip hit. If the button is held, the whip will goes as it goes when you hold the attack button with Nathan, it'll go spinning around very fast. But the duration cannot be held very long since it'll cover a large area.
First hit : 2%
Second hit : 5%
Last hit : 7%
Forward tilt : Ice. Fair range, a bit of startup but deals a blow that freezes the ennemy. 6%
Down tilt : Earth. Simon whips the Earth and then in front of him quickly, allowing him to make jump his ennemis with the first hit as if they were hit by a POW block. It'll send them up Simon at the second hit. 3 and 9%
Up tilt : Grass. Good range, brings ennemies at Simon, allows follow-ups. 5%
Nair : Lighting. Extremly fast and deals 12%, and paralyzies the ennemy.
Fair : Holy. Fast and deals 10%. Describes and arc in front of Simon, sweetspot at end.
Bair : Dark. Slow but deals 20%. Circle hit but described by a whip hit that'll go from front of Simon, to quickly behind him, dealing damage during the entire movement. Sweetspot at end, ofc.
Dair : Poison. Deals 5%, and the ennemy will be consumed by poison during 15 seconds, 2%/hit. Obviously, Simon whips down him and sweetspot at the end of the whip that'll meteor.
Uair : Stone. It will freeze in air the opponent like Ryu's focus attack does when she hits a midair ennemy, then send them flying, deals 17%. Straight up him.
Grab : Simon throws the whip and circles the ennemy with it while bringing him back at the same time.
Forward throw : He fires his whip while unwinding the ennemy, 1% for each second he burns for a 6% total, then deals a forward ice hit of 4%.
Up throw : He unwinds the whip in order to throw the ennemy in the air with a dark whip hit of 7%, then deals a holy whip blow of 8%. Killing throw.
Down throw : He whips a bit weakly two times with the poison whip, dealing 3% at each hit, then he deals a great stone whip blow that damages 6%.
Forward Smash : Ice & Fire at the same time. No charged : 15%. Mid charged : 20% Full charged : 25%.
Extrrremly good range, it would go almost at the half of Final Destination if full charged, but in a simple line.
Down Smash : Earth & Grass. Simon lands a single but fast spinning whip-hit, which will touch ennemies on the ground and midair ennemies as well.
Deals 22% if not charged, 25% if half, and 28% if full.
Up Smash : Holy & Dark, idem, deals 30% full charged, 25 if not, and 27 if half.
It'll go this way : Like Jonathan's diagonal down-right attack in midair but there it'd go from left to diagonal up-right, and then go back up Simon, but straight up. It's like he tries to get the strength of the great movement he does in order to get the whip straight up with more strength. I know, it's not well explained...
All of this moveset applies for the Whip Special, UpB there, Final Smash, keep that in mind.