There are links in the OP for recommended mods and links to mod guides or you could try GOG's forums, they tend to sticky the mods for each game in its forum. If you've never played the games before, your best bet it to just stick to the widescreen/bug/fix mods and not add in a ton of content.
All the infinity engine games (and the other ones you listed - NWN ToEE) from GOG definitely work fine for the most part, of course with PCs, you'll always run in to situations where a certain configuration might cause issues others don't have. OS compatibility shouldn't be an issue, they all list XP, Vista, 7 & 8 (I've been running 7 for a few years and have had no troubles). Some people experience slowdown in the infinity engine games for example, and there's a few ways to fix it outlined in mod post, but it may not be necessary depending on your setup. I'd be pretty confident in saying that any issue which can come up with any of the popular games from this sale has already come up for someone else and been solved.