Well was it ever explained how Acina became empress or how many jedi and sith are left and what happened with most of the previous dark council?

How many jedi are still alive how many sith are there is there still an jedi council? Does the alliance have more force users then the empire or the jedi?

If any of this are answered can someone point to where?

During Fallen Empire Lana states that after the war with Zakuul Acina was the only Dark Council member still standing (the others being presumed dead) and she assumed the title of Empress. Obviously, that's not entirely true since Vowrawn was the Imperial representative who is shown in the Fallen Empire cutscene kneeling before Valkorian, and Vowrawn is still sitting on the Dark Council in JUS and Onslaught (unless Acina dies on Iokath). Unit strengths on either side have yet to be fully revealed. It is alluded that since the Jedi are mostly in hiding the Empire has a larger force of Force users on their side, but we haven't been given any numbers. Likewise, we haven't been given any information about the Jedi Council, but the end of Onslaught on Pub side alludes to something coming in a later update.

As far as the Alliance goes, we haven't been given any numbers about the strength of Alliance forces, whether that be their fleet, troops, Force users, etc. A convenient plot device the writers frequently use is to say that the Alliance is strong but lacks the strength to do... whatever you suggest the Alliance could do.