I have experience with both. The galaxy rasboras would be too small in my opinion to be with the angels....would only be a matter of time before they became snacks.
You shouldn't be afraid of the rummynose. They are not extremely sensitive. As long as the stock you buy is healthy, a bit of a slow acclimation to the new tank and as long as you keep your water parameters within normal range for ammonia, nitrite and nitrate, with regular water changes, the rummies should be fine.
It is true that their noses will be bright red when all is well with the water in the tank and they are reported to not have red noses if the water quality is deteriorating so if you haven't been paying proper attention to the water, they'll let you know by being pale. I never saw them display any sensitivity to my water and mine are in with my discus where nitrates tend to run a little on the higher side.
They are easy to feed and peaceful!