Migration of users/groups to Azure active directory from multiple forest

Hi,

We have one requirement to integrate/move  users/groups from  multi-forest, multi-domain AD environment to Azure Active directory and manage the password of users. I knew that FIM provides the AAD connector to move the user/groups object  to AAD. Request you please suggest me for the below.

1. Where we need to deployee FIM - On premise or on cloud? 

2. Whats are the others main things we need to consider  for solution.

3 What about the FIM SSPR. Does it support the password reset on AAD.

4. is there any document for it?

Thanks

Harry