Our youngest child is 2 and I would predict we have about 23 years of reaching this goal.

Depends on the state but a parent can transfer by family transfer their primary residence to their child without property tax in California up to a million dollars. 

She has basically asked us if he can move in November 1st and has already assumed it would be fine with us…We are not comfortable with the situation and are trying to figure out what our options are.

Property Taxes: Should be safe since you plan on living in the home (because it's a primary residence, should be excempt with parent/child exemption), but you would want to get a second opinion on this.

When I refer to the owners when communicating to the tenant I really mean the wife, child, and myself but do not provide that detail.  

It's way too common for Landlords to get too comfortable and chummy with the renter/handyman.

It sounds like they are coming from a place where they don't know nearly as much as you about rentals, so it's your job to teach them in a way that makes them feel comfortable.

Such as things you wouldn't be comfortable talking about here or elsewhere.

Do child support liens assigned to individual drop off like mechanics liens if the home ends up going to auction?

Here are a couple pieces of advice I have for you or any new beginner:Start investing as soon as possible, not as soon as your comfortable.