just a warning if a shrimp will fit in a fishes mouth it will be food. even if it does not fully fit in its mouth (say guppies or small tetras like neons) it will end up being food more than likely. its been know for shrimp to be ripped apart and eaten. most people who keep shrimp keep them in shrimp only tanks. if its a must to have both fish and shrimp i would start with shrimp and let their numbers build up alot then add fish since you know some will get eaten.
as for temps i know your not out of the woods yet on really cold temps, i live in N.E. oklahoma about 20 miles south of caney and also lived out by garden city and i know its cold till mid march. if you get stuff mailed to you i would wait till after the first of the year to avoid all the christmas mailing. and im sure if you really want shrimp you can find them in the swap and shop way cheaper than at your lfs. cherrys go for a buck or so now so there is no reason to pay $8 per shrimp there