If I do sell them, it will be a turnkey solution, or because the demand is there and it just makes sense to do so.

We share a number of things in common - I'm also an engineer by day, have most of my real-estate investment locally in buy/hold multi-family, and have a similar set of goals to those you articulated. 

You need to build rapport over a common interest, get them comfortable, and logically explain your offer. 45 offers is awesome.

For the initial loan to obtain a property, does it make sense to go with a shorter term 15-year fixed and then refi to a 30-year fixed after 6-12 months?

Here is a blog where I wrote about a recent 42 unit we bought and did creative things to add value. https://www.biggerpockets.com/renewsblog/bought-multi-million-dollar-apartment-complex-age-26/Just a few ways to produce ancillary income:- Laundry Coin laundryDetergent/laundry essentials in a vending machine in the common area laundry rooms.Rent individual W/D to each unit-Parking Garage parkingCovered parkingprime spot parkingJust plain old charge for parking-Renovations Interior units upgradesCommon area renovationExterior upgrades for curb appeal-Vending machines In common areas such as exercise room, pool house, laundry or leasing office-Trash pick up service In high-end buildings they have a service where you can set trash outside your door and for a fee maintenance will go around each night and collect it so the resident doesn't have to carry it to the dumpster.

You really need to know your market and what your long term goals for the property are to decide what makes sense.

In addition to that, banks will only finance against the "lot rent" component of rented mobile homes on land.A $150,000 Park would need about 12 homes with a lot rent of $200 per month assuming a 50% expense ratio and 10% capitalization rate.If none of this makes sense to you I would highly recommend the Mobile Home University Due Diligence Manual.  

See if you kind find some common things you can relate to them about either through conversation or items seen in the house and use that to build rapport.

He's been here before...TX laws seem fairly landlord-friendly, or at least written with some common sense, so the best course of action is to have the owner sit down and write out absolutely everything he can remember.

. $3000-$4000 makes sense.