Best idea is to contact your local flooring dealer and ask for the number of a recommended floor installer.

Code specifies where cleanouts have to be installed. 

This would create a clean aesthetic look of the new bathtub/shower install.2) Cut a portion of the floor on the right side out and sink the bathtub to rest on the actual joists?  

I haven't really tried calling any commercial gate installers, but I imagine they would charge me quite a bit.

in them;All the trim (baseboards, casings, window boxes) were unsalvageable;14' of the sill plate along the rear wall and 12' along the front wall had to be replaced - this was the big discovery which put us in framing mode for a few days in-between snow storms.We discovered that the vapour barrier was, for the most part, ineffective due to poor installation - the insulation looked like a tired air filter in a shop vac.  

Called pest professionals and they came in to seal holes and install a one way door that later was removed.

You will be creating new point loads under each end of the new beam, so you will more than likely have to install new masonry piers and footings at those areas under the house.

A new heating sytem was also installed 5 years ago. 

If you know who installed the system u may want to just call and ask them. 

Florida homes are built on a slab so to install proper ac/heating you have to cut channels or venting channels in the concrete/floor you could come through the attic but that's not green and a professional would advise against it, is the ac your biggest desire to update?