I've not had basically anything you've named, so take what I'm about to say with much salt, its based on my readings of what others have expressed. You may also wish to review the
"Never Again" [found it!] thread of birds people won't buy again (and more importantly, why they wouldn't - since needs vary).
EEs are mutts, no matter what name gets attached to them, Americana or Green Egger or whatever. That said, they are popular, lay colored eggs, and seem pretty run of the mill based on reports I've read. Meet your needs just fine.
Silkies are high maintenance, prone to issues with larger birds, likely to be the bottom of almost any pecking order. Not good for egg production, either - I'd avoid.
Left central TX last year and some months, I remember the heat. Traded it for almost as hot, and much more humid, FL. Any bird can tolerate the heat with good coop design and some additional considerations during high stress periods (electrolyte support, ice blocks in the water, frozen fruit treats, etc), but if you have the choice (and you do), I'd recommend seeking out small to moderate sized birds with clean legs and pronounced combs to help with heat dissipation.
Particularly as you aren't looking for meat birds, there's no reason to seek out poultry with large body mass or a walking feather pillow. Brahma I'd definitely avoid for reasons I put in the NeverAgain thread. Orpingtons and Cochin, cute though they can be are big, heavy fluff balls, I'd probably steer clear.
White Australorp, Barnevelder (infrequent eggs but good color, a nice brown with red tint, Buttercups (no idea where to find them), the Egyptian birds (name escapes me) - very good with heat but not known for egg size or frequency and a semi-unique look to them, Marans (in the lighter colors, cuckoo very pretty) have nice dark brown eggs), Minorca, RedCaps (McMurray carries, not sure who else does), Welsummer would all be good choices.
/edit and of course I'd try to get the whole flock at the same time to ease integration.
What hatchery are you planning to use? that may help us target what's available to you in the desired timeframe....