It will be based on your FICO, ability to pay, DTI, and they'll order an appraisal.

I'm inclined to think that postcards / yellow letters may get brushed aside, so something that looks like a bill or an official notice may do the trick, possibly with a more formal message inside?

When you rent by room; tenants ability to get along well/live well with heir housemates matters.

You are therefore afforded a bit of stability.Your ability to raise the rent is based on the lease.  

I'm with you, windowless envelopes are the way to go.Windowed envelopes have the connotation of being a bill, credit card offer, or spam mail and we do not want our letters to scream "SPAM!!"

Where as an apartment if a tenant moves out, it will not have an impact on you having the ability to make the mortgage payment.

I don' have the ability to predict like the Magic 8 Ball (remember those?)

I've never had good luck working with a significant other in the same job, but again, that's me not you.RE is amazing and I see myself eventually becoming full time as well, but for the moment I love my corporate work and it is what funds my ability to be an investor. 

"If Buyer has an ownership interest in more than X units in the community, during the term of the loan Buyer agrees to rebate half of the rents received for all units to Seller as compensation for Seller's increased risk that Buyer's finances may change as a result of HOA actions and may lessen Buyer's ability to repay this loan."

Then I would suggest putting in an offer with an inspection contingency to allow you time to visit the site/area personally, but giving yourself the ability to back out if you aren't comfortable.