you really need to try several films and do your own testing.
as for the gear....
- 50mm Distagon lens.
good choice, i use the 40mm for extra wide, filters are a headache though
- 180mm Sonnar lens.
good lens but not sure why you need it
- Individual shades (I thought that the pro shade is too must hassle).
- Spotmeter. Probably the Gossen Starlite.
i would go with a sekonic 608 personally so you can use it in studio etc in future
- A second A12 back.
- PolaPlus back.
- 16mm extension tube (for portraits with the 180).
too tight for portraits imho
- Lowepro Nature Trekker AW II.
will you be doing macro? why not buy the 120 mackro/planar, its great. good for portraits too.
a prism would be very useful also.