The pleather pads are designed to offer a tad more isolation as 32 ohm are the "mobile" version. I personally don't mind them at all for comfort (they currently have black velour on them though).
The pleather replacements are harder to find and need to be sure they're the "fenestrated" version and not the extra isolating version made for DT770M.
The genuine regular velour pads fit the same and don't alter the sound much. EDT 770 are what you're after.
Take note that the pads have a surprisingly large effect on the tone. I put 880 pads on mine out of interest and it sounded god-awful. For this reason I would stick to genuine DT770 pads rather than cheap aftermarket ones.
My DT770 and qudelix are primarily for watching movies.
You would need either a different amp/dac that receives optical or a different media source like a media PC to play media from/attach your qudelix.
But really you are wasting money by not just using Bluetooth to your qudelix. You're not going to notice a difference, and from a technical perspective I'd be surprised if a high quality stereo BT transmission is the compression/quality bottleneck when streaming movies anyway.
At worst I would buy a standalone BT transmitter with higher BT standard/better radio if your TV is lacking.