If you do a search through the forum, I think you'll find a lot of advice to avoid Dreamweaver if you can help it. There aren't any "gotchas" that are peculiar to DreamHost in terms of Dreamweaver support, at least that I've heard of, but a number of the folks here have a lot of dislike for Dreamweaver in general.
To the meat of your question, the basic plan is probably sufficient unless you're creating a highly dynamic site that does a lot of processing or database access. Dreamweaver templates probably don't qualify as that, so odds are good you'll find performance to be just fine. I don't have any direct experience with them, though, so please take that assertion with a grain of salt.
In any case, you can always sign up and take the hosting for a spin. DreamHost offers a nice upgrade path if you find your site needs more performance than the shared plan offers, or you can cancel for a full refund within the first 97 days if you think another host might be better for you.
Best of luck!