I have dual bionic ears (hearing aids) as well and am not far behind you in age either for whatever that is worth. I have a real issue mixing with them as the do "color" the sound, just as you say. The solution mix wise for me is to bounce my mixes off trusted friends that mix well and matching reference songs to my songs I am recording.
For chord changes and timing it will come. But you want to work on doing it the 'right way' and not practicing wrong ways that become habits. The right was is a pain but in our cases very much helpful. Count out your songs and chord changes. Like this: 1 2 3 4, 1 2 3 4, chord change before the next 1 and so on. Of course this is just an example and your song will be different count wise. But hopefully you get the idea. By doing the counting you really take a lot of the "hearing" part out of the picture and start to rely on repeatable mechanics. Justin will teach you this, just hang in there and have patience. Not an easy thing to do mind you!