Im in Charleston South Carolina... you'll be about an hour and a half to the coast and any salt water but there are plenty of lakes around there for fresh water... To answert them 1 by 1..
1) You don't need any expensive equipment... once you get down here all you need is a roll of kite string, a chicken neck and a dip net...
2) Crawfish are more up your neck of the woods. Lobster... they are here but you have to dive the reefs and wrecks off shore to get them...
3)Fresh- Better up near Columbia Salt- Anywhere down here from the North Carolina border to the GA border is good fishin. We have it all including Tarpon and we actually had a few bonefish caught up in Myrtle Beach this summer...
4) You can catch triggers here but they taste much better than putting them in a tank...
I am not sure about catching fish for aquariums, I think you need a permit for it...
5) like he said yes but crowded in the summer. A lot of beaches will not let you fish from them in the summer.
6) Absolutely... just watch out for the sharks... the nearshore reefs near the harbor I wouldn;t dive, LOTS of big bull and tiger sharks, the off shore reefs and the ones up and down the coast I have heard are OK... stay away form the nearshore reefs near river mouths..
7) We have barrier islands that are pretty close to shore, easy kayak paddle and they are either protected or run as state parks and are VERY nice..
South Carolina will suit yo just fine. Just remember you are in the south, Be nice, obey the creel limits and you'll get along just fine. You can also check out
www.charlestonfishing.com
this is my local forum that has TONS of good info.. good luck and tight lines...