All,
I'm thinking this should be sufficient, no? It's going to be about 50% HT, 40% Karaoke, and 10% music. The basement will not have carpeting. What do you guys think?

If you don't have carpet, you really need to put down some throw rug or remnants, between you and your speakers or first reflections will really skew your sound performance.

The new 350v3 will most likely be adequate for that room size, however the best overall freq response across all seating positions results with multiple subs.