Depends on several things, really. Does your AVR have all the features you want? Do you listen to movies at conversational volumes or at sports stadium levels? What's the distance between your primary listening position and your speakers? But most likely, yes, they'll probably be fine.
I think you're on a very good track, shopping for the nicest mains you can afford, planning to add a center channel a little later, and possibly surrounds after that. This is much better than we typically see from people looking to cram 7.1 speakers into a 2.0 speaker budget. Build piece-by-piece, and the end result will be much more satisfactory than a full set of mediocre speakers all at once.
Re: subwoofer not needed, I doubt that all would agree. If you were buying these speakers for music and the music you listen to never goes below the bass guitar range, then yes, these would be very fine without a sub. But given that you intend to buy a center channel later, I'm guessing you intend to use these for movies as well. A grown-up subwoofer or two that can pressurize your space is pretty exciting in movies.
With that in mind, I might suggest a pair of capable bookshelf speakers instead + a subwoofer. The
Hsu Research Hybrid 2 might be worth considering (assuming your room is 4000 cubic feet or less). And yes, they'd work well with your receiver.