personally I wouldn't bother with the fine combination stone unless you are sharpening carving tools. For most other knives 1000 is fine enough.
as for the other bits, if you actually need them, then I have been doing something very wrong for a long time!
I hold my stones in a support made from a length of roofing batton (3.4x2" crappy wood, surplus from building project) and bakedbean can. Cut a piece 8" long and two bits 2" long. Screw the short lengths to the ends of teh long length and the stone will fit between them. I cut a couple of strips of tin and nailed them to the sides of the batton so that the stone won't slide sideways. This is then screwed to a table, clamped in a vice, nailed to a fence post, etc depending on where I am suing the stone
I've never found the need for the basin either. I store my stones drya dn soak before use ina bucket of water. I have an old washingup bottle with clean watewr in it to irrigate the stone as I go.
Also never found the need for the nag stone. It's purpose is to produce a finer polish than the stone's grit size would dictate. Since I am stropping with a polishing compound on it, there is no need for the extra consumable
just my humble, tight fisted, thoughts