We don't need sprinklers here, but if we would, I'd either do that or replace the lawn with gravel or something else maintenance free.

I feel that I don't have enough experience to know if I could do better or worse.

Would anyone care to recommend a bank, credit union, etc that will do a HELOC on an investment property?

Loan Diversification = Do not stack up a bunch of one loan product for your portfolio.

Quote from @Bernard Golden: Quote from @John Underwood: Do you work on RE full time?

We want to do this transaction so we can upgrade our living space, have another rental (our existing house), and eventually rent out the new house (his house) after we grow out of it.

Where do I even start?

Let us know what you decide to do. 

Ideas such as what are  Very focused certificates or training that young people can do in order to get a base income very quickly. 

But absolutely be very clear with the seller as to what you're doing.