So it looks like the Momentums due to hiss and Symphony's due to lack of deep bass rumble are off the list, and the h8's and possibly p5's (depending how they perform on your final test) are on order!
I don't recall if you said you watched TV (streaming or otherwise), so you might not consider this a legit test subject. I watched 'Residue' (UK) with the B&W P5's and thought they got a decent workout.
The first 5 minutes of Series 1/Ep. 1 had bass-heavy dance club scenes; a large explosion; sub-bass rumble sound elements in it's overall sound design with a bassy score and theme song. Lots of undelying good vibrations. It continued on through all 3 episodes of series 1 (There are only 3.)
The P5's handled it all with no problem. I've been loving them all along with my own music and stuff I'm streaming now, plus other movies and TV shows, so I expected as much.
I could not detect any hiss or buzz. TV sound recording is different than movies, but I think they've gotten very sophisticated with it. Everything I heard during quiet moments between dialogue or music was ambient/atmospheric in nature as it changed with each room or tunnel or street they were in and fit the scene appropriately. (Remember, I have a USB dongle and watch on a laptop.)
The mids and highs--especially in dialogue were good, but I like the Fidelio's better. Basically the same as the B&O H8's. The only time I had a problem with them was when the characters were yelling into phones or over radios and walkie-talkies or through gas masks, etc. I'm chalking that up to TV recording anomalies and my ears. During normal speech, they were very pleasant sounding to me and well integrated into the overall sound design. But that's where you would have to test them yourself to determine what is acceptable.
They are as comfortable as the other 2 on-ear we've discussed. The rounded rectangular pads maybe even provide a more even pressure pattern on the similarly shaped ear as opposed to round pads. (Or, you could take up smoking so you have to remove them and go outside every 45-60 minutes--Hey!
All of my headphones are perfectly comfortable using this method...