Well, MY minimum would be:
1. Changing bag, the larger the better. Cheap either new or on eBay
2. Stainless steel tank and reels. I would never buy one with a capacity of fewer than 4 35mm reels
3. Chemicals to taste. I like Diafine. Seeing as how you are shooting Tri-X and Plus-X I would bet you would too.
4. A coat hanger and some clothes pins to hang the film to dry in the bathroom.
5. Negative sleeves. I like Adorama's poly sleeves that fit a ring binder.
That's about it.
Nothing fancy is needed at all.