You will have roommates that will supplement your payment which is a great idea.   

Also, I think for a 3-bedroom I will need some cadets anyway to supplement the heating.Are there any other options I should consider?

Living with roommates to supplement the mortgage and pay down in order to build/create equity.

Look at percentage of income with gym membership versus residuals ( personal training income, selling of supplements and vitamins, special event classes,etc.).    

Agents will give you supplemental information sometimes with the MLS listings however i would just do your research on your own.

Frankly any fund needing a line of credit to supplement their funding for making loans or buying loans isn't doing a good job on raising more capital! 

. * Example * I want to invest in Multi-family properties in Albuquerque, NM because the properties and their taxes are dirt cheap; Looking to create many funnels there to supplement completing my income goal, so I can quit my day job! 

If you won’t miss the 25k and you could easily spare a few grand out of your pocket without it effecting you’re life then go for it and wait 15 years to reap the rewards, but if you want supplemental income and accelerated wealth growth pass and keep looking.

My end goal is to supplement my income and transition out of my day job into a lifestyle similar to Mr.

Rent supplements will not change that fact.Again there is zero proof to show that rent supplements impacts how long tenants stay.