In addition to what @Moses Kagan  says, the biggest thing that I see (after doing a bit of homework) is that walking into a situation with pre existing tenants in a rent control building (who handle their rental obligations in a timely manner) is a positive one from the viewpoint that you walk into a situation with pre existing income to service your (debt) mortgage right out of the gate.So let's say those tenants are under "rent control" stipulations which means you can't go and raise their rents over 3% of what existing rents are.

However I did not invest in crowdfunded deals.Do you think the treatment of investors would be any better if the sponsors had pre-existing relationships with the investors, and personal reputations on the line?

These rules include having a preexisting relationship with any non-accredited investors that invest in your deals. 

If we did a pre existing building I would go after and old shopko, ace hardware, grocery store, walgreen building.  

The electrical also was pre-existing at purchase but how old is difficult to tell (but it is Romax)  2) 2 of the items pre-date my ownership 3) the process is non trivial.  

You will need to work with an attorney or find a pre-existing form.

You can’t ask people that you don’t have a “pre-existing relationship” with to invest with you.

Also, does the preexisting relationship hinder investing in such a note once it is sold?

Since most syndications are 506-B deals, you are required to have a preexisting relationship with at least one of the general partners before investing.

If you do not wish to purchase all/some of these homes for a quick flip or long-term holdings then perhaps you wish to wholesale or bird-dog some of these leads to active MH investors in the area.I do know of some folks in the central Florida area that are actively investing in mobile homes inside pre-existing communities and attached to private land.