-Spoil bank refers to the area adjacent to areas that have been dredged. I.E, the ship channel or intercoastal waterway. This is a popular summer time way to catch fish, especially with live bait. I wouldnt attempt this however unless you can take or talk to somebody with first hand experience. May not be best idea for the kiddo's anyway.
-shell pads are just that, oyster shell reefs. A great place to fish as it provides structure in an other wise nothing bay. This is where people often "drift" as you mentioned, which is just that, killing the engine and drifting (letting the tide or wind push you) over an area you believe will hold fish (like a reef). If your not familiar with reef systems be careful, at low tide if your running full tilt through the bay and hit a reef you could be in trouble.
-Slick are a great sign that fish are in the area. When you see an area of water that looks like someone spilled a small bit of oil, it's because thats what it is, oil on the surface of the water, it's caused by fish going into a feeding frenzy and the oil from the baitfish they are eating is being regurgitated and floats on top of the water. Look for 10x10 to 20X20 or sometimes larger continual areas of this, usually a round shape. don't confuse these with wind slicks however which are never round. they say if the slick has the smell of watermelon then it is fresh.
-free lining. You will most likely use live shrimp for bait, which is a good choice for you. Free lining is just what it sounds like. You hook the shrimp and add only a split-shot weight maybe 6-8 inches above the hook that should give you just enough weight to cast and no more. Let the live shrimp drift in the water and do his thing. Alternatively you can fish live bait with what we refer to as a "popping cork." The popping cork is usually seperated from the hook by about 18-25 inches where you hook the bait. You can just cast them and let them sit, but they are called popping corks for a reason. They are usually bright colors (orange yellow or pink) and have rattles on them. The idea is that you "pop" or pull the cork toward you every few seconds. This attracts fish as it sounds like bait in distress. Look for "mansfield maulers" or something like that at academy.
-Also, I don't know if you know how to hook a shrimp but here you go. Use a circle hook or treble hook. when you hold the shrimp and look at its head you should see a small "horn" run the hook just below that and avoid the black spot. Some people prefer hooking through the tail.
-You will not be catching "mullet" just so you know. They are a bait fish. However, those fish you see jumping are mullet, and if you see a lot of them jumping and acting nervously, it probably mean there are speckled trout or reds in the area feeding on them. Like you said, you just want to make the girls happy, so with bait, even if you don't get into the trout or the reds, there should be enough hardhead catfish and other "trash" fish which can actually be fun to catch to keep there attention. Sand trout, whiting and croaker are all actually good to eat if you get into a mess of those. Hardheads however are not.
-On location, being in a ski boat your not ideal with for bay conditions (bay boats are designed to run shallow) but lets not get nit-picky, a boat is a boat and if your careful you should be fine, just don't run full-tilt if your not aware of the terrain or depth of the area. The coves you mentioned are not a bad idea. You just shouldnt run too far into them. Stay close to the mouth. If the tide is outgoing, it will pull the baitfish in it out and the trout reds and flounder will be waiting. Also, look for birds. If you see birds working an area and diving for fish, GO. Mainly key on gulls, terns and smaller birds can help sometime but also will lie to you. In galveston bay, we mainly key on the coves and shoreline marshes like you say, and reefs, whichever you are more comfortable doing, just don't push it, you have precious cargo.
Rememer. The bay is nothing like a lake, West Bay where you are does not really get deeper than ten feet. Most of it is 4-6 in fact. Be careful like I said of reefs and just plain running to shallow. It can be tricky if your not used to it. U may think you are fine because it looks like your 100 yards or so from shore but the water could be less than a foot especially at low tide. It may be easier for you to just anchor somewhere with your set up. If you have live bait and are just trying to catch fish, this is fine. The San Luis pass is obviously a very popular reason for an area. You could either anchor in the pass or behind it on an incoming tide and probably have success, just respect the current and tide.
-time to go. Like most fishing and hunting, sunrise and sunset are popular for a reason. especially in the dog days of summer, this is sometimes the only time the fish will bite. The other factor in the fish bite which you may not be used to is tides. The main thing is that when the tide is moving, it is good. This means the bait is moving with the tide, and the fish are moving also, often waiting to ambush bait fish being dragged by the current. The other factor is lunar fases. These are both long subjects to discuss and I don't understand them fully myself. so grab a gulf coast connections or gulf coast fisherman magazine. It will have a tidal and lunar chart showing you the best times and may have some other good advice.
Sorry if this got long, just trying to avoid school and would rather talk about something I enjoy.
Tight lines.
