the minnow sold in most shops is the mummichog, aka fathead, killie, etc. I believe the latin is fundulus hetreroclitis, but is been a while. There are a number of other common killie fishes common to our marshes but, for whatever reason, are generally not used as bait. The striped killie fish, f. magalis, get bigger in size and appears to be a great bait minnow. very commonly caught by cast net throwers along the bay, but Ive tried them numerous times and have never had anything but a bluefish touch them..... and they dont count.
I fished the Houston area with my brother-inlaw for large mouth bass. He said we were using "South Texas Racing Minnows" but they didn't seem any faster to me. He got a 8.92 pound bass---I got a Bully-gator--16.7 pound Cat fish. Oh well !
When you get into freshwater you run into shiners, dace, chubs, small suckers, etc. I usually use small bluegills for bait when I'm fishing in bass country. I don't mess around with the small stuff anymore. If it can't swallow a whole bluegill, I don't want to take it off my hook .
I would have to say yes. Look at what the Bass Assassins and Finn-S minnows resemble. They are killer weakfish lures and they look like silversides. Are you planning on using them live or dead? The top two natural baits I've found for weakfish are soft crab and cut spot. Live spot for the big tiderunners.