The first answer is yes, you definitely can't put any points into Magicka if your using this, same with Stamina if your using Unlimited Stamina.
For the second one, basically what you'd have to do is have 1 set item that gives you the Unlimited Bonus (Galdur's Amulet for example), after you've achieved Unlimited Concentration Casting, you can equip other Fortify Magicka items (Not sure, but they might have to be full numbers, so you couldn't use Fortify Resto to boost them) and still have UCC active and working fine.
The first answer is yes, you definitely can't put any points into Magicka if your using this, same with Stamina if your using Unlimited Stamina.
For the second one, basically what you'd have to do is have 1 set item that gives you the Unlimited Bonus (Galdur's Amulet for example), after you've achieved Unlimited Concentration Casting, you can equip other Fortify Magicka items (Not sure, but they might have to be full numbers, so you couldn't use Fortify Resto to boost them) and still have UCC active and working fine.