Hey dude, I came in here after I realised your post included still life. What I listed isn't suited to that, it's just for portraiture. For still life, your considerations are quite different.
If I shoot still life, I generally use diffusion panels, flags and bare bulbs, as the light needs to be far more finely controlled than portraiture. So in that sense, I can't really help advise you on what materials will serve both portraiture and still life, as the equipment needed is so different. At least two softboxes would be a minimum in my opinion though, and plenty of black card to flag off portions of light once you get more advanced.
The reflector is fine, though I'd just beware of anything off Ebay. The reason it's cheap is because it's poorly made.
The umbrella is probably rather large for what you'll be attempting at the beginning. The smaller you keep your contrasty light sources (such as an umbrella), the better you'll eventually come to understand the light they produce. Grab yourself a smaller umbrella and do some headshots or 3/4 shots. An 83cm brolly will light an entire room with ugly shadows if you don't know how to control it.
The softbox looks OK, but in all likelihood, it's a piece of crap that'll fall apart in a month. It's also an s-type fit, which is for Bowens, Interfit and other manufacturers of lights, and won't fit your flashes without an adaptor.
Grab yourself something like this:
http://www.calumetphoto.co.uk/eng/product/lastolite_ezybox_hotshoe_38x38cm/753-173a
It's expensive in comparison to the Ebay softbox, but the upshot is that it's actually built for your needs, and is relatively sturdy. It's also far more portable.
Brackets absolutely fine. Shoot through umbrellas are bloody big, and I'd debate whether you really had enough power in the flashes to get a decent light through them. I could be wrong though, my speedlight knowledge is limited.
As far as the light stand goes, I'd avoid elemental like the plague. They have the worst construction of any manufacturer I've ever come across. Jump on Ebay and grab yourself a couple of crap ones for a fiver, they'll probably last you longer.
Good luck dude.