Mario -

SOme of the links in your first list of 4 items are to RA and SM versions. Was that intentional? I'd get a quote on all non-SM non-RA versions and see what that comes out to. I recall the fixer (regular C41) being much cheaper than what you have listed. I think a case of 4 1 gal bottles to make 20 or 25 gallons was about $40 or something. bleach is expensive no matter what version you buy, but it lasts a long time. (ok, not "forever" but essentially... ;-)

the solutions keep well. unmixed I have had C41 dev be fine for a year or more. Mixed, it's more like 6-8 weeks at most. Fix: lasts fine, from what I can tell so far (2+ years on unmixed solution). Bleach seems to last fine mixed or unmixed. Rinse seems to last fine (years) as it's basically just photoflo.

control strips are for processing to see if your C41 line is in order. You likely need a densitometer to use those, but they can be handy if you are getting strange results or want to run a really tight line (as far as specs of the processes). Mostly they are something a commercial lab would use to insure accurate processing. I've never run them but get great results nonetheless.