My ideas for Bomberman now...
B: Bomb Drop/Charge
Tap to drop the bomb where you are, where it will eventually produce a small explosion after a brief period of time. Hold B to make the bomb larger, creating a larger, but quicker explosion upon release. Be careful, as bombs can also harm Bomberman if you're not careful. You can also move bombs with your other attacks or throws, but be careful not to heavily attack it too up close.
B Up: Rocket Blast
Bomberman jets upward with a flaming jetpack. Can be angled before lift off, but will generally stick to one direction for the long burst.
B Forward: Rooey Rush
Bomberman hops onto this kangaroo-like creature, which then leaps forward, then disappears right after. This gives Bomberman an additional momentum attack and recovery option.
B Down: Bomb Fuse
Bomberman uses this move to take an elemental property, either from an item, part of the stage, or a projectile thrown at him, and snags it to merge with one of his bombs to change its property. This will change the type of bombs he uses for his neutral special. Throwing-wise, they’ll mostly act the same, unless otherwise noted, but their explosions will have different properties. For example, if there is nothing directly near you, or an air-type projectile, you'll get a Wind Bomb, which can create tornados instead of regular explosions. Ice, Water, Fire, Electricity, and Poison result in fairly expected effects and bomb types. Taking from shadowy/dark energy will create a Gravity Bomb, releasing a miniature black hole that sucks in foes. Light energy can result in the Light Bomb, which creates a dome of light upon exploding which will temporarily slow time for any foe caught in its path. Taking from metal will create a Pierce Bomb, which can be thrown to destroy certain items or terrain before blowing up, as well as doing extra damage to foes hit by it even before exploding. Ground/Rock/Grass/Wood/Cloth all get generalized to create the Navarm Bomb for Bomberman, which sprays lava around in four directions, which can also create small bursts of flame, as well. Plastic/Rubber will, naturally, get you a Rubber Bomb, which bounces around when hit or thrown, much like a bouncing ball. It will explode eventually, though.
Final Smash: Skull Bomb
Bomberman charges up a massive bomb that eventually has a skull appear on it. He then leaps up above the heavy bomb he's hoisted and then tosses it onto the stage, where it then explodes in a massive cross/t shaped explosion.
Now Shovel Knight, as well...
A: Digging. Shovel Knight digs with his shovel. This moves somewhat slower than most A combos, but can hit hard, and has a utility beyond just simply jabbing with the shovel, being able to potentially uncover items, as well as acting as essentially an extra quick grab and back-throw for Shovel Knight.
Down-Air: Shovel Drop
SK tilts his shovel straight downward and bashes down, which can also bounce upward off of foes or the ground,
much like a certain wealthy Scottish duck.
Other Relics and Special Attacks (in the Shovel Knight sense) will get used for certain moves, like the Dust Knuckles for the Dash Attack, the Throwing Anchor for the Up-Smash, the Fishing Rod for a long-range grab and throws, as well as a potential tether recovery, and the Charge Slash for a Down-Smash.
But this is what I ended up choosing for his Specials (in the Smash Bros. sense)
B: Flare Wand
SK swats out this wand and shoots out a fireball, which travels straight-forward, moves slightly slower than Mario's fireball, but hits somewhat harder. You can also do an extra bit of damage up close by hitting a foe with the wand.
B Up: Propeller Dagger
SK holds this dagger outward, which then starts spinning like a helicopter blade. SK can angle this in multiple directions to travel upward for a brief period, and it also serves as a multi-hitting move to those in his path.
B Side: Chaos Sphere
I ultimately decided on this over the Alchemy Coin or Mobile Gear because I thought digging served the purpose of potentially gaining treasure/items for Shovel Knight, and the Propeller Dagger seemed like more of a signature recovery option for SK. You can shoot out up to two of these bouncing green energy spheres to move along the ground and do damage to foes, though they will disappear after a period of time, but during the time they are active, you cannot shoot out any more.
B Down: Phase Locket
SK uses this to briefly become completely intangible for about 3 seconds. There's a cooldown between each use, and you could potentially be vulnerable if you used this in the air or timed it poorly, but while in use, nothing can harm you whatsoever.
Final Smash: Catch Her!
The background changes to a more dream-like one as Shovel Knight sees Shield Knight fall from the sky towards him. If he can catch her, the two will then perform a tag-team attack on the nearest foes, smacking with the shovel and bouncing them against the shield before sending them flying. Alternatively, you could go with the War Horn, but this felt more tied into SK's character.