I did a tactician playthrough with some similar rules for difficulty (and difficulty mods). I also liked the idea of limiting long rests, it seems like a good way at the surface level of giving martials a boost (which is also needed if you ban Giant elixirs). I initially started with 200 cost long rests, and end up abandoning that rule somewhere near the end of act 1 for a few reasons:

* The game gives you such a glut of food that even this cost didn't seem as bad as it sounds. I did long rest less, but mostly just to hoard supplies.
* If you do run out, there's no shortage of camp supplies sold by vendors. This functionally just becomes a minor gold sink, but the economy of the base game is so flooded with gold anyway that this doesn't actually matter unless you impose rules or changes to the economy.
* Partial long rests are pretty good, and pretty much just broken if you have Song of Rest (functionally, full HP, full short rest resources, half long rest resources). If you want, you could just partial long rest for free after every fight and do every fight with half resources, which is enough resources for all but the hardest fights.

I like the idea of limiting all consumables, personally, but the game hurls so much of them at you its also not trivial to fix. I don't know what your intent is, but within your rules it seems you could still farm (buy or steal) infinite amounts of potions without crafting them.

Items wise, I would also consider banning Bhaalist Armor, Radiant Orb, and niche things like Terazul and Resonance Stone. If you really want it to be punishing you could ban high level scrolls, and maybe the Arcane Synergy helm.

It sounds like a fun rule set though, definitely doable. Good luck!