I checked again to make sure, and when I don enough magic items to boost my Restoration to above 50, I am still unable to cast that level spell that I purchased just for that occasion. I have enough magicka, but the message comes up "you are not high-enough level to perform that spell", or similar.
It's frustrating, especially in Oblivion instances, because once I've finished a fight with a few high-level enemies, my health is so low that it takes me a long time to refill, and I usually have to wait for my magicka to refill just to finish. I could use potions, since I'm maxxing my Alchemy just for that, but the fact remains that, using only my low-level Restoration spells to level up will take a loooong time. I guess I'll have to forego more important fighting instruction-levelups, just to use them for Restoration, which seems silly.
I really hope that I'm not understanding the results, otherwise, I'm fearing a broken game event later.
EDIT: Now I have yet another problem; when I use the Alchemy table at Battlecrag, no matter what ingredients I use, the health potion ends up weighing 2 lbs! ....
All of this works as intended.
Fortifications don't give you the perks. But with Magic fortifications will lower casting costs. This was mentioned in post 2.
The Frostcrag alchemy stations does not technically "fortify" instead it adds a temporary "ability". So in Frostcrag you do get the perks with alchemy.
The one bug appears to be with alchemy. Fortifications to alchemy are useless, unfortunately.
As far as the weight of the potions, that is set when you first mix the potion with a certain set of alchemy equipment or skill level. Then all other potions of the same type use that weight until the equipment/skill level changes. If you name the potion something different it should show up with the new weight.