Can i backup databases inside virtual machines?

Agents for VMware and Hyper-V back up the virtual machines in a consistent state, provided that...

 Can i backup MS SQL

Yes, Acronis Agents use Microsoft Volume Shadow Copy Service to back up Microsoft Exchange,...

 Is it possible to do file-level recovery from the (image) backups in the local storage?

Yes, it is possible.

 Is there a way to limit network usage for backups?

Yes, bandwidth limitation is an option of each backup plan.