Generally one chooses the speakers/subs first, then use an amp with appropriate power/impedance handling for your purposes (and with connectivity and feature set that also works best for your purposes). Speakers are a rather personal choice as to how they sound, tho (unlike most well designed amps, which would sound same/similar within their limits) and have never even seen a Dali or Q Acoustics speaker myself so couldn't even comment on your proposed choices, pick the pair you prefer.
Whether you want towers doesn't mean the towers don't need a sub(s) (and subs give you better placement choices for that range of frequencies, as the L/R speakers may not be in the best position for such let alone have the same capability). Towers may have more capability for spl and perhaps bass extension in a general sense, but there are very good bookshelf/standmount speakers out there too.
Subwoofer use with many 2ch integrated amps will be with no or limited bass management, so that's something to think about as well.
As to these two integrated amps, the Yamaha looks to be the better value to me but didn't dig thru all their features but I'm not in the market for one either.