Nice looking plant! Don’t worry about crowding, they’re often grown like this to look bushier overall in the pot. It’s your choice if you want to divide them, you don’t have to - but people often do. Maybe the lure of getting two plants for the price of one? They look healthy enough to cope with that being done anytime, but the ideal time is early summer, so they’ve had the growing time of spring to recharge after winter and still have a few months of growing time of summer ahead of them.

As far as the brown spots on the leaves go, this is a common problem and nearly always comes down to the soil and how you’re watering. I recommend you search this problem on the Houseplants forum, and also look at some of Al’s threads eg. Good Growing Practices - An Overview for Beginners. Then if you have specific questions try posting them on that forum, you’ll probably get more response over there as this forum is more for edible figs :)

Thanks so much!