Hey Steven,
If all the numbers you state are correct then I would definitely say it sounds like a good deal. You really have to the time in to figure out the actual numbers though.
You should get actual MLS sold comparisons on all the properties to determine ARV. Get with a realtor to get this.
You should get actual rent comparisons as well from your realtor to make sure they are in line with what youre saying.
I dont think its necessary to get an appraisal and inspection before you submit the offer, just put the offer in and make it contingent on inspection. This way you can get the inspection done after you have it under contract and find out what really needs to be done with the houses. This would be the time you can also get a contractor into each property and give you actual prices of how much it would cost to repair all the houses. If it comes out horribly wrong and way more then you thought you can back out because of you inspection contingency.
As for financing, my understanding is that it varies from bank to bank. You say you have a loan officer on your side so those questions should be directed toward him. He should be able to tell you what the seasoning requirements are and how much LTV. Im pretty sure that if you dont wait a year to refinance the bank will only offer a loan of up to 70% of the purchase price, not the appraisal. But like I said, your loan officer should be able to answer that too.
Make sure you have the answers to all that before you commit because the last thing you want to do is buy all that, rehab it and find out you cant refi like you want.