3 SEPM's

I currently have 2 SEPM using 1 SQL server, servicing 1800 clients.  Everything is currently running Server 12 R2.  I was thinking of spinning up another SEPM to help with the load.  I was curious if 1) If it's possible to run 3+ SEPMS accessing one database. 2) If possible, do I have to stay with 2012R2 or can I use 2016 for the new SEPM?

I appreciate any guidance.