How far back the banks will review rental payments is going to vary from bank to bank.

There is lots of room for varying opinions.

i have a varied portfolio with SFH and multi-family.

Landlord tenant law varies by state.So I can't comment on the laws of your state.I will tell you here in Georgia I can't just say "get out" if they don't meet my demands.Generally if the 1 year term expires then the tenant is month to month with the exact provisions that were in the 1 year lease.Here if I my lease was ending and I wanted to raise rents then I would need to give the tenant 30 days notice.If the tenant did not agree to the new amount then they can inform the landlord they will not agree to the new amount.Then I have to give the tenants 60 days to find another place PROVIDED that they pull the full rent and comply with all the terms of the lease in place that was converted to month to month.So you just can't kick them out and certain procedures have to be followed.

The process varies between where u r closing.

Hardcore rate/term shopping lenders for a 1st position mortgage isn't going to make a huge amount of difference (relative to also comparing reliability, knowledge, etc), but for HELOCs it will because the rates/terms vary so much in the HELOC world.Often, but not always, regional banks or credit unions will be the winners. 

There's so many varying factors associated with local markets that you can't possibly know not being from the area.

How you structure payments can vary.

Again this can vary by market, but in my years here in Chicago, haven't seen a TON of money made. 

Please note that the MAO for that property will vary based on the actual ARV, repair costs and your fee.