My roommate in college constantly doubts the importance of finance, real estate investing, and entrepreneurship.

That roommate paid $400/mo all utilities included.  

Can I get a conventional loan on a primary residence and then convert it to an LLC if I want to have roommates or rent it out when I'm not there so I'm protected? 

Ok, I agree it has served me well with the few I've done and allowed me to quit my day job with income left over to save a tad monthly based on a very modest lifestyle.I have been fortunate to have great tenants, amazing even, with just 1 that was a nuisance to the other roommates and I was able to get rid of with minimal cost. ( Mark you, this tenant I didnt completly vet except for the background and credit checks, then handed him over to someone else to complete the process).

Or we can rent extra  rooms ( 5 bed/3 bathroom currently one roommate pays $800) at $600 to 700, so total rental fee will be $1400 ~$1500 from renting two rooms.

Use the house hack to bring in roommates and drop your expenses while saving big for more investments. 

(Orahh, btw) If you can get people to be roommates with, all the better!

The second issue I am having is that I would prefer to live in a condo preferably a 2bdrm by myself where I can rent out the other bedroom if I want to or need to on AirBNB( If the condo board and NYS still allow it) or to a roommate.

Last year I gave each of my tenants (3 roommates in my only unit at that time) mugs from Anthropologie with a gold foil initial for each of their first names.  

We also learned he got himself an unauthorized roommate; some big guy who made his living selling drugs out of my house.