Zero problem with estrogen with BO, you can keep both going and it shouldn't be a problem.
The most usual eye colour change is that the pigment can become brighter or stronger, for example if your eyes are blue, HRT can make them much more vibrant blue.

Mine has been somewhat strange as they're completely different now, but it seems that the greens have strengthened a lot while grey faded to the background and there's less blues than before. Its so strange as I didn't first know it could happen and then things just started changing and whole lot of pigments are very different now. Only complaint I have is that I do not tan smoothly like I used to, but my face now gets fuckton of tiny freckles which look like I'm dirty rather than tanned. Arms do the same thing.
Also hair colour can become deeper and stronger, I dunno if mine changed much, other than getting some new greys in last cuople of years.
Oh by the way, body odour change is absolutely to be expected. Also you might notice you will start to sweat very differently and probably much less than before. That leads to less need of taking showers all the time which might help with skin and hair quality. I have benefitted a lot from not needing as much shower or sauna these days. I love it as with crazy sensitive skin that's a must to survive without being broken somehow all the time.
These things really sound like BO is starting to work on you, keep at it. I hope you get HRT sorted out nicely. That's a whole another world, so much to look forward to.