Thank you all!!
Plumber came by this am and looked at everything. His opinion was that the fitting was just fine and wouldn't cause me issues, said the water in that pipe wasn't anything to worry about. I disagree based on what I've read and said that given this great opportunity to do things better with the bathroom being opened up that I want the fitting that the manual states is the correct one. He said he would replace it to what I want and given the space the new fixture would need to be cut in lower (which if used in the first place would have avoided the cutting of the joist). Coming in lower will avoid any pipe in the joist space and a new 2x8 beam with be attached next to the one that was cut.
What confused me and I didn't have the knowledge to reply very much was that he said the double combination fixture wouldn't be to code. I don't understand how that would be. I looked up Fla code and this is what it states (see chart below),
"706.3 Installation of fittings.
Fittings shall be installed to guide sewage and waste in the
direction of flow. Change in direction shall be made by
fittings installed in accordance with
Table 706.3. Change in direction by combination fittings, side
inlets or increasers shall be installed in accordance with Table
706.3 based on the pattern of flow created by the fitting.
Double sanitary tee patterns shall not receive the discharge of
back-to-back water closets and fixtures or appliances with
pumping action discharge.
Exception:
Back-to-back water closet connections to double sanitary tees
shall be permitted where the horizontal developed length
between the outlet of the water closet and
the connection to the double sanitary tee pattern is 18 inches
(457 mm) or greater."
Also I'm confused about a double fixture fitting vs double wye fitting- what is the difference and how do I make sure they use the right one?