Excellent for pulling the trigger on the sub! IMHO, that's the most significant component of your HT, and anything you do from here on out will at least sound great, if not excellent. The advice that follows is nit pickery, really. But it is what it is.
The Ascend Acoustics speakers will tolerate wall-mounting better than the Pioneers I think.
I've read that the Ascends are OK with only having a few inches between speaker and wall, whereas the Pioneers' little 4" drivers need as much room to breathe through the rear ports as they can get. Also, the Pioneers don't have any mounting holes. They're stands-only. Another thing that makes the Ascend a better choice is that they're higher sensitivity and higher power handling.
But if you do end up choosing the Pioneer, I don't think there'll be any other drawback to using all bookshelfs instead of towers up front. I think they'll reach well below the traditional 80Hz LFE crosover point.
The reason I recommended the Denon E300 (or E400 or any of the X-thousand models) is because of the Audyssey room correction. I think you'll get better results, especially with bass correction, with Audyssey than with the Yamaha's YPAO. Also, Audyssey Dynamic EQ is ossum.