Will these fit 3m worktunes am/fm with bluetooth?

Hello - These can work with 3M Worktunes.

Will these fit peltor comtac iii?

I used them on the Peltor Sport Tactical 500 headset. They fit perfectly, but you have to align them up accurately before they snap into place. Once you know how to do it, it's easy to do. Took me several tries to get it just right. The Amazon site for the gel pads says, "3M - GEL-HYG Gel Hearing Protector Replacement Ear Cushion Hygiene Kit, 1 pair, works with WorkTunes (90543), Peltor Sport (97040, 97041, 97042, TAC300, TAC500, 90565 and 90566)." When you say "peltor comtac iii" are you referring to the TAC300 model? If so, they're listed as compatible. If you have any doubts, you contact Peltor for your answers.

Well these work with either 3M PELTOR X4B or 3M PELTOR X5B behind the head ear muffs?

They work with the 3M black and red over head ear muffs. That’s all I know.

Worktunes Connect has a flat surface for the pad, however these have a lip or ridge. How can they be used?

Great question! The WorkTunes(TM) Connect sealing rings have the pad that is attached to a hard plastic base that fits in the WorkTunes(TM). When replacing, the hard plastic base that the sealing rings are attached to, should be removed as well.