1. Some lenders allow using rental income even without two years' landlord experience. Others do need.
2. For primary home purchase, if your loan amount less than 417k, you can always get a loan no matter how many financed properties you have. 4 or 10 is ok. I have a client with 13 loans, we are still able to get a primary home purchase loan.
3. Lender will calculate the qualified income for self-employeed. Again, it's case by case. Depends how you deduct on your tax returns, depends on your company(S Corp, C corp etc). Then the requirement a little bit differnt. But two years self-employment is a must.