I’m with @Rduke77, and I recommend ditching Karil.
Here’s my problem with Ulmer–He does very minor damage and reduces defense on heroes that I’m not even ready to bring down. In offense, Valen serves me better even in Very Fast scenarios. I don’t have time to play debuff in Very Fast tourneys when my people are dropping. I find it’s far more valuable to bring down a single target. Ulmer does not hit like a truck; he just debuffs. Good for defense, I’m sure, but there are alternatives (Gunnar) so I’m not sure I care enough.
So the next question is–Will you actually get around to leveling Ulmer, or will you always be drawing more appealing blues to level for the next 3 years? Is Ulmer at level 1? If so, when will you actually level him? If you already know you’ll always have better things to do, then you may as well scrap him. You’ll draw him again later anyway. He’s not hard to come by.
All this being said, I have no experience fighting with or against Ulmer’s costume or costume bonus.
Gato has his uses, and it’s nice to have more than one 3* blue sniper.
The others I’m a fan of, and I recommend you keep them all. Even if you don’t use them soon and it takes 8 months before you start on them, they are valuable.