1 is definitely not happening, atleast not for a while. Demand for the trunk is very high right now with just the e92 328/335's and it will only grow higher as people take delivery of the e92 m3 and want the CSL style trunk.
2 is already in the process. Longs diffuser was actually made to fit the OEM dual setup. The quad version i guess was not ready yet so he got the dual setup and custom trimmed it to fit the quads.
3 and 4 is probably going to happen sooner or later down the line. I remember reading something from Vorsteiner posting on m3 post saying they will be making add on lips as well as full bumper replacements for the e92 m3. Im sure if they see enough interest, they will do the same for the non M e92's.