I got a couple quotes to install 4 smoke detectors - $1200 and $750.

Looking for best recommendations when it comes to security cameras, motion sensor lights, key pad locks, ring cameras?

Unfortunately with tenants you can't trust them to keep up with things like replacing furnace/ductless filters,  smoke detector batteries,  or sometimes even light bulbs.   

Do check ins every 6 months-check the furnace filter and batteries in the smoke detectors/CO detectors to make sure they are working. 

Motion activated flood lights and cameras.

We stopped by one of our houses the other day to check smoke detectors and asked if anything was giving them issues.

Selling would also be a hassle if it's not permitted since the next buyer will go through these same motions.

By changing any of those, you then are required to update the code for the room, which would most likely add to your list the requirement to add a smoke detector, which may not already be present in the room if it is not a new home.Now, that is the RIGHT way to do the conversion. 

To my understanding too, you can rent your property out while you wait for the inspection and results, and if you miss some items on the inspection they're pretty easy to work with to get it remediated (In my inspection I was missing a smoke detector in the basement and they let me send photos when it was installed).

Install some cameras and motion lights to the front.