Drysuit is a must for Lake Erie diving. I see people try it in wetsuits and some say it's fine. Everyone I've seen on the wrecks in Erie who dived wet had fun. For about the 1st 10 minutes. Or once they got below 40-50 feet and the cold hit them like a sledgehammer.
As an instructor who teaches at Crusty's and has had students in Erie, I consider taking students into Erie in wet suits to be dangerous and irresponsible. Hypothermia is a very real risk and potentially fatal in a number of ways.
Crusty's is still going to be colder in May (depending on the weather leading up to it) until you get towards the end. Beginning of May the water was still in the 50s and (40s below 20 feet) we dived dry only.
There aren't really any photogenic wrecks in Erie in less than 80 feet of water. Anything shallower is a jumble of planks and rusting metal. Vis is generally poor shallower than 100 feet.
For photography forget about an agency class. Find a good underwater photographer who makes most of their living with a camera. There is one up in Baden, Pa and another in Columbus, Ohio (this one has shot for Nat Geo, Discovery, Smithsonian, etc.) who I recommend. I also shoot UW but I'm not at the point where I can teach a class on it that I would feel is worth the cost.
I do offer a workshop for skills for UW photography (buoyancy, trim, camera weighting, environmental awareness, and buddy skills for photographers). The I refer you to one of the pro's for the actual photo stuff. They don't want to waste time teaching you how to dive. You should know that before you go to them.
I'm the author of the SDI Drysuit course and manual. I also have a couple books of my own that are useful for new divers and those considering taking up the activity. They can be acquired through Amazon or by sending me a PM. I always have a few on hand signed.