It sounds like you've got a similar level of hearing to my partner (barakta over on YACF, she's not on CycleChat). She has a severe/profound hearing loss, uses BAHAs, and gets phenomenal results from them - she has very good speech and most people don't realise she's deaf unless they notice the electronics attached to her head, but without them she *might* hear a car horn if she was sitting on the bonnet...
She has multiple disabilities including balance and arm problems as well as the deafness, and has only been able to cycle since we bought and modified the controls of an ICE recumbent trike a couple of years ago. As she wasn't confident at riding in traffic (or indeed navigation) we had to find a solution for her hearing me while cycling (one-handed signing without eye contact is fine for pointing out potholes and so on, but not so good for more complicated instructions).
As the BAHA stands free of the skin on its abutment, it doesn't suffer from sweat ingress like a BTE aid, but wind noise is still a problem. After unsuccessful experimentation with adding foam to the BAHA to act as a windshield, we ended up using her FMGenie radio link (which she has for meetings at work) to bypass the BAHA's internal microphone, with me wearing the transmitter pack under my jersey, which shields it from the wind. The radio range isn't fantastic (100m or so at best), but it's sufficient that she can usually hear me better than I can hear her - especially when she's riding in front (I'm hearing, but struggle to discriminate speech in noisy environments such as wind, traffic, music, running water and the like). I made a waterproof cover for the BAHA to keep it from drowning in wet weather (BAHAs aren't very compatible with headwear, though a single layer of Buff is okay), as you can't get waterproof covers for them like you can for BTEs. The FMGenie receiver lives in the waterproof pocket in the back of the trike seat, and the cable is as annoying as that of any body-worn aid. This works well when we're cycling together, but has the problem that in larger groups she can only hear me (or someone riding close to me), even if other people are closer to her. Fine if the group are aware that that's how it works, but not a very scalable solution.
I've also cycled with BSL-using Deaf friends (who are competent cyclists, so didn't need a running commentary on what to do with gears or how to negotiate traffic) on a few occasions, without trouble. We just pulled over whenever we needed to communicate anything that one-handed signing or pointing at things couldn't convey.
To be honest, I don't think you really need that much hearing to cycle in a group, as long as the group are thoughtful and aware that you can't hear. The biggest issue is knowing where you're going (either by not riding at the front so you can follow, or by having a pre-agreed route on a map/routesheet/gps/whatever). Most critical group-riding instructions are by hand signals, anyway. If there's a change of plan, or you have to have a complicated conversation, the group can always stop.
Of course, I'm talking about the sort of loose group you get on forum social / CTC / Audax type rides, where you usually leave enough space to react to what the person in front is doing. A tight paceline where there really isn't any margin for error is probably a different matter - I don't know, I'm not that sort of cyclist.
I don't know what your speech is like, but people may well find it harder to understand you while riding - especially if there's background noise that you're not aware of, so don't speak loudly enough to be heard over. My partner and I use simple hand signals (hand slowly opening or closing) to indicate that she should change her speech loudness without interrupting what she's saying - useful in all sorts of day to day situations, as well as on the bike.
Hope some of that helps...
