That's how I've been running and have not noticed any issues with NPM 10.1. We just migrated to 10.2 last week and haven't noticed any impact yet.
Yes, they are polled by the poller you selected in the discovery profile so they would not all be running on the main server at one time. As long as its not too much for your database server, I don't see how you will have any issues.
Hope this helps.