If your seals fixes the coolant in the case problem, to clear moisture you could fill the case with kerosene(I know sounds bad) and just kick it over a time or two and drain that out. I had to do this once from dropping it in a river, but I would also suggest filling the whole case with oil and letting it set for a while if you use the kero. You cant beat it for getting moisture out but I worry that it strips the oil from between the plates, hence filling it full of oil. Drain it again, put some more oil in and run it for a little bit.
But if you just drain it and let it sit with the plug out for a little bit, run some oil through it, fill it to level and ride it for a little bit you should be ok. It may fog the window a little bit but if you change your gear oil regular you'll get it all out.