How many makuta where active/alive after the revolt? ( rough estimation is ok)
Currently there is only one alive is Miserix.
What exactly do you mean with that?
At the end of the canon story there were two Makuta still alive: Miserix and the Alternate Teridax whom Mazeka brought with him from the Melding Alternate Universe.
I think he means after Teridax overthrew Miserax.
Given that there were only ever one hundred Prime Universe Makuta in existence, and that the five that sided with Miserix seem to have been immediately put to death after his defeat, that would leave ninety-five still alive and kicking directly after the revolt.
And as said before, the only one remaining now is Miserix, though the Alternate Teridax who returned with Mazeka is technically still running around as well. This information can all be found on the Makuta (Species) Page over at BS01.
In that case the exact number was never given. Maximum is 95, but I personally believe that some more Makuta already died prior to that.
Yes I am talking about when teridax overthrew miserix to be clear