Well, you have posted to the backplate/wing (BP/W) capital of the world! Right here on SB. You might find that BC recommendations are outnumbered about 20:1 by BP/Ws.
Before anyone can say anything about what kind of equipment may be reasonable, you need to describe where you want to dive. If you are doing cold water then there is some variation between wetsuit and drysuit diving. If you are just going to do resort dives, the equipment needs are less demanding.
It seems both have adequate lift for wetsuit diving but I can't say anything about drysuit. Either will work for warm water diving.
However, I'm not a fan of integrated weights. It's really a matter of age and a trashed back. My tank, regulator and BP/W weigh about 50#. If I were to add my lead to the rig, it would be 70#. I DO NOT want to try to lift 70#. Now, it's true that you can don the BC and then insert the weight pockets, and that is probably the right way to do it, but I'm just not convinced.
OK, here it is: Decide what kind of diving you want to do. Warm, cold, drysuit, wetsuit and just call Tobin at Deep Sea Supply. He can help you pick a BP/W that will be a lot more comfortable and a lot less bulky.
There are alternatives for carrying weights. Personally, I use a DUI Weight & Trim Classic harness. Since I dive in cold water with a wetsuit, it would be nice if a) my rig could float itself without the buoyancy of my wetsuit and b) I can float while wearing my weight harness without my BP/W. Soi, it's a matter of getting the right amount of weight in the right place. Oh, and I want to keep the BP/W weight down to something reasonable. My 30# wing won't float 20# of lead, a 5# backplate and a tank that is 11# negative when full. My wetsuit probably has something like 25# of initial buoyancy and I only wear 20# of weight in the harness. Everything sort of works.
You have the right idea about buying your gear ahead of time. You will, however, make no friends with your local dive shop (LDS) when they find out there is nothing for them to sell. Selling classes doesn't keep the doors open. Selling overpriced dive gear does that.
In terms of the OW class, I would avoid the friction by a) taking the class from a shop I never intend to revisit and b) using rental gear. That way when I have the OW cert and show up at the shop I really intend to use with a full bag of gear, they don't have anything to say. I would already be a trained diver and expected to have my gear. This thing gets very predatory. Really ugly! YMMV but don't count on it!
Another approach is to do the confined water dives locally with rental gear, buy your gear and travel somewhere warm for the open water portion. Or just take the whole program somewhere warm. Warm is good...
Richard