Well, just have in mind that for a Ficus, roots popping up doesn't necessarily mean they're out of room to grow them in the soil, Ficus like to put some roots on the edge as you can see in the nature..., but yes, too much can be a sign...
About loosing leaves, doesn't seem to be a problem, looks like a stress reaction.
Did you prunned or removed the soil from it's root mass? Because then it would be even more expected/normal...
When water supply reduces (doesn't mean you not watering enough, just that the plan is absorbing less) the plant itself drop some leaves (even green ones) not to dehydrate... So as it is showing new ones coming, and it's close to growing season again, shouldn't be any problem...
Don't water it moderately, water it normally, a lot of water when it's slightly dry above...
You can start to fertilize when the tree shows a nice growth so it won't lack nutrients in the process, and when it's ready to take direct sunlight, so it can grow healthly as possible... Just make sure not to do it all at once...
Here's my ficus after a drastic pruneing and after a repot in mid Jan. (early summer for me)...
After a weak or two it started backbudding as you can see in the picture, so I started to fertilize it (with organic! Castor Cake, which is really high on nitrogen and slow releasing fertilizer, I made it myself, I already used NPK too, but I feel more comfortable with organic, and the tree likes it as much)...
And this is almost a month after, I'm not even prunning, just letting it grow wild for now... It takes full sun the whole day after 10 am. on this spot...