I'm sorry, but what? They're almost freaking identical. Even Corrin has similar mobility! Copy and paste stats, templates, makes easy, simple money. The Fire Emblem cast plus Shulk have similar mobility however subtle like how all of them have the same dash to stop or shield frames, grab frame data, and even moves that it's sickening at times.
I could argue that all of the Fire Emblem characters are semi-clones to each other and it's easy to see with Lucina, Marth, and Roy and Ike and Shulk. Corrin and Robin are basically Lucina hitboxes plus Ike's mobility or worse and a projectile. No wonder the developers didn't want Chrom in because that would be 4 Marths: Chrom, Lucina, Marth, and Roy, and 8 semi-clones: Chrom, Corrin, Ike, Lucina, Marth, Robin, Roy, and Shulk. Am I overgeneralizing? Hell yes, but the point stands that they share similar data that it's really questionable.
I don't agree with this. You need this so a Fire Emblem character feels like a Fire Emblem character.
I think it's more clever than lazy. The amount of work done is the same in most situations (except the two Marth clones). Examples off of the top of my head of FE attributes:
- Robin has Marth's Melee/Brawl autocancel windows (except Nair), Brawl total frames
- Roy with a couple of Melee Marth's aerial total frames
- Roy with the same knockback values and angles as Melee on many moves, especially his throws
- Everyone with a 1.5 initial dash
- Grab start-up data like you mentioned
- The really short (Ike, Corrin) or really long (M, L, R, Robin?) initial dashes
- Roy and Robin with the same 95 weight
- Corrin and Ike with the same 0.092 gravity and 1.65 fall speed
- Corrin and Robin same 1.0 air speed
- Corrin with Roy's Melee 1.2 walk speed
- Corrin and Ike's 1.5 run speed
- Corrin and Ike's 0.04 air acceleration
- Corrin's Melee Marth tipper Fair angle (kind of... 65 vs 67 degrees)
- Roy, Melee Marth, and Melee Roy's 0.03 air acceleration
- Counters to represent the turn-based gameplay and turn-based battle animations
- Robin keeping track of weapon usage/durability is pure Fire Emblem
- Robin's Kris color palette (New Mystery of the Emblem's Avatar) and other palettes' resemblances
- Marth with a Roy palette, an ally unit palette, an enemy unit palette, and whatever else
There's more but my point is that I like all the reproduction. You can easy come up with random, different numbers but why would you when this effectively gives a franchise an identity in a game that represents many franchises. They all do this, it's not just FE. Mario, Pokemon, etc. do this in their own ways in Smash.