The "buff" Ameraucana (sounds like an Easter Egger) will give you either black offspring with orange leakage, or half orangey brown, half black mottled/pencilled birds, depending on if she's a true buff with unwanted black or just a Wheaten or Duckwing w/columbian.
The other "Ameraucana" will just give you black birchen-esque colored birds, the males will have white and red leakage, females will have brown leakage at the neck. Some might be pure black (the females)
The Sex-Link will either pass on white birds or birds who are mostly black. Males may have some reddish or orange coloration in the neck/wings
The Welsummer will pass on birds that look like brown-reds/gold birchens. Mostly black females with likely orangey reddish necks, males with orangey-reddish necks, wings, saddle.
The RIR will do the same but likely with more coloration than the Welsummer crosses.
If the rooster is carrying a silver gene or two, you may also have offspring with white/silver leakage instead of orangey-brown.
Most of your chicks will be born either black or black with brown/yellow faces. The "buff ameraucana" offspring may be born quite brown looking though, like an adorable fuzzy brownie bite.
ETA - If any chicks are born yellow w/striping or light brown w/striping or a nice bright yellow in general, you likely have a rooster carrying recessive Wheaten, Duckwing,or Partridge. You'd notice it in his hackle or saddle though if you inspect his color closely.
Your Sexlink will indeed throw some white chicks though, so if pale white or yellow chicks are born and feather out white or yellow for more than a week, that's the Sexlink/Comet's chicks,