My question is

im on the last? mission on NOD on orginal Tiberian Wars

and im stuck on a little island. and i build up my base there, but i must move from this island

but i cant nore build a new "Command Center" ore a new "Rafidandery"

the basic question is. cant i only have 1 MCV on a mission? and is it un-deployable for gooda fter placing it?

One of the GDI missions which I remember good you are able to build multible MCV:s.
And I believe you can build multible MCV:s on the last mission of NOD too.
And they are un-deployable; after you deploy them once they stay as the main structure untill selled or destroied.

But that's odd, you should be able to build infinitive of Rafinaders if you had the cash/money.

However, you can only have one Temple of NOD, and after you have launched the Nuclear missile you will be unable to use it again.
So use the Missile wisely on the last mission.