What should I keep in mind for storing wool roving?
When it comes to wool, I think the biggest issue is moths. You don't want the wool to be eaten, so to store it somewhere where the moths cannot come, is a good idea to start with.
Then, constant moderate temperature and humidity sound like a good idea as you don't want the wool to dry out, become less soft, those kind of things. You're mentioning that the wool has a variety of colours, so I assume that it's painted and not all natural colours in different shades of white and brown? In that case, the wool grease has probably been removed, and drying out is less of a problem.
I myself have a lot of raw wool (including grease, dirt, pieces of grass and sometimes a dead beetle) for at least 10 years and I actually never did anything special to store it. The wool gets less greasy over time, but as long as there are no moths in the wool, you can do with it whatever you want.
(P.S.: Be aware that felt is a moth magnet!)