Absolutely use a lawyer and include ever possible detail covering all conceivable situation.Never leave any financial aspect open to individual interpretation.

Because rates are so low, you could conceivably just keep this mortgage forever (thus avoiding double closing costs), and simply use your other money to buy the next one and the next one.

If our future project are similar to this one, he’d make his money back in 4-5 flips, and we could conceivably grow this business to a point where 25% of profits becomes a very large number year over year.I don’t really know what’s fair here, looking for any advice at all.

So it's conceivable that you could find a place perfect for you that is less than the property you are selling.I'd then balance my debt so I take more on the primary and use excess cash to pay down or off the new rental. 

It is conceivably possible to do a 1031 exchange  several time to where a lot of your equity in the property is owed to taxes... so just would encourage you to make sure you totally understand the concept and execution.I personally like your house hacking idea better for a beginner... way less down payment, you live in it for a year and then move out and rent it. 

With Rently or Showmojo, you could conceivably do it.

I don’t think there is much value in the unit itself, but If we were to put it up for sale, would it be conceivable that people might pay more for it because of where it’s located?

I'm trying to get in the 'if you can conceive it, believe in it, then you will achieve it' way of thought.

BiggerPockets is definitely the place to be to learn all you need to know about every conceivable niche there is.On a side note, we're about to close on an apartment building down in Port Charlotte in six weeks or so, so I'll be down close to your neck of the woods.

Check out Guerrilla Marketing Weapons by Jay Conrad Levinson, its a short cheap read about every conceivable way he can think of to market products/services.