Since you have such a diverse flock, I believe it comes down to what you want from your Rooster.
All things being equal, I would normally go for the breed documented traits, although individual birds personalities can ( and often do) deviate from the norms.
Having said that, Leghorns have a reputation of being “nervous” and some have noted the Silver Lace is usually the dominant member of a flock.
If I were you, I think I would ask myself what I REALLY want from a Rooster and wait and see if there is actually a “problem” prior to eliminating one or the other from the flock.
...my $.02 !
BT