Does anyone recommend using an online service, or is it better to just write the seller a check every month? 

I use Quickbooks and have managed the properties using classes in one Quickbooks file BUT with 2 separate checking accounts (one for 2 houses, and one for 1 house) . 

Also I'm not familiar with Connecticut foreclosure laws concerning state tax liens, so best to check with a creditors rights attorney in the state. 

Now when we check references - at least 2, but we want 3 - I like to ask about communication (of course) but now it’s more about response time than getting updates.

Check into transactional funding.

Comparing your property taxes to others, and checking that the insurance covers the increased value, or replacement value, are just as important as keeping current with comparable rents.

He was excited about that.I went over to check out the property and was pleasantly surprised.

I checked with my GC and although he's been involved in new construction and is confident in his abilities to complete the project, he is not able to show 5 completed projects.

Maybe borrow the remaining down payment with a personal loan, car title loan (a real one, at a bank for 5-9% interest), CC balance transfer check at 0% for 18 months (assuming you have a plan to pay it back), etc.If you wanted to make the house your personal residence, you could put down 5% and pay PMI for a year.  

You can check out details on their Facebook page if you are interested in attending and potentially networking.