Can I revive the dead already in Mausoleum?

No, you aren't able to do that. That power works only on skeletons. Once the deceased are buried, their departure is permanent. However, it's a tricky thing reviving the dead, and it isn't always successful.

Thank you

I didn't know we could do that! I tried in the mausoleum without success. So you can revive a skelton? Good news. I've only gone through the whole game once, so my next time I'll try that. Thanks.

Question about the mausoleum, once you open it up do you have to dismantle the blocking totem? My villagers won't dismantle it.
They just walk away and shake their heads.

I had 2 or 3 die before I had the mausoleum. Now I have it, and they are not in it

Unfortunately, there are trade-offs in how you approach the game's challenges and which ones your elect to complete first. The mausoleum is an essential pre-requisite for burial of deceased villagers. From the game guide:

I've tried to revive one Elder four times and see his "spirit" come back but then he vanishes and the skeleton is still there. I will attest to the "isn't always successful part. For some reason the villagers still celebrate though.

Presumably that Elder died of old age. His lifespan isn't extended by the revive power so he promptly dies again. If you've had a villager die of sickness or starvation, though, he would be restored in full.

Does anyone know how many villagers can rest in the mausoleum?

I have revived dead people over and over trying to keep all of them alive for ever. Unfortunatly It is impossible and five have died so far. I revived one villager who I named Nox after the flower in plant tycoon died right after I revived him. My oldest villager is named Dodi I have revived him over and over and he seems to live quite a while after I revive him. The first time he died he was 74 now he is 82. I hope to get him to the age of 100 then I will let him rest in peace.

I have reached limit a while ago, its 100 rows and 5 villagers per row so 500 villagers, rest get carried to there but won't appear on list.

Thank you, VVCX!
My villagers have now reached row number 70 in the mausoleum ...

I'm way ahead of you, Candy. I now have 84 rows completely full.

It would sure be nice if you could delete some graves in the mausoleum so you would be able to save them for your fav villagers. Like my 27 living EEs and JOATs. It's sad knowing when I forget to grant youth on them they wouldn't get a grave.

Anyway, thanks VVCX!