I just got a quote for architectural blueprints for permits and engineer stamp for $ 3250.00So, I'm getting that started, while I'm looking for a contractor to do the work, as the scope of that work is more than I have dealt with in the past

I was able to find three tenants and no problems with turning on their electricity within Lake Worth Utilities.

We plan to replace with tankless water heaters and in-unit high-velocity small duct central heat and air (using electric baseboard for the garden unit heat), and also remove all the radiators from the building.With the furnace and water heater removed, we would like to knock down the walls dividing the current furnace room, and make one larger rear, which is the bulk of the remodeling work to be done. don't not currently have drawings or architectural plans.

Depending on the price of the total deal, you should be able to develop the other 2 new builds for about $65psf-$75psf with a good contractor.

Will I be likely to face lawsuits and liens related to the work done by the auction buyer and his contractors (the lien period won't close for a few months.) 

Other one was electrical work , where The loose breakers were checked and wiring was adjusted and validated if appliances are working.

If you are a realtor, property manager, or contractor in one of these locations please reach out as well.

I understand that a lot of investors just use general contractors or their own expertise, but I am curious if maybe something like same day home inspections would be helpful, since some deals can get snatched quickly?

I think you should ask the seller last time what does it take ($) to sign the contract or you can tell her best you can do is offer say $60K with quick closing as condition. 

With an excellent contractor and property manager these can be fantastic investments.