Background Info: I purchased my house two years ago as a "two bathroom" home in Maryland. The home was built in 1968 and was completely remodeled before we purchased it. After about a month we realized the upstairs and downstairs tub's were not draining correctly (They were not vented). We ended up ripping out the downstairs tub (saw there was not even a trap under it) replaced some copper drain pipe with pvc and installed a vent. The upstairs bath now vents correctly. The pvc in the pictures drains the upstairs bathroom sink and tub and also vents through the roof.
We would like to just make the down stairs bathroom a half bath, putting a toilet were the tub was (the area where there is not tile). The iron pipe is 3.5" OD. The pvc going up is 1.5".
1) Will a toilet install work where I've noted?
2) Should I install a rear outlet or wall mount toilet so there is a little additional fall on the line, or will just cutting a trench in the slab work?
3) Once I get the cast iron reducer off, should i just install a fernco to connect the cast iron with pvc 3x3x1.5 Santee?
The block of wood in the hole is nothing, just a piece of scrap that fell in when doing some deconstruction. Thanks in advance, and sorry for being a little long winded...