can the namekians and majins get swords staffs etc

If you mean a master class then yes one is an axe and the other is a claw

tell me all the namekian and majjin wepons they can get plz

Not really sure about majins since i don't use them i only know that karma majin gets a mask and Ultimate Majin gets a horn

Nameks- Shadow knight axe Dark warrior claw. Majins ult majin instrument grand mask( not to sure on both of them) no idea for plasmas and karmas

Sub-weapons are locked into their classes.

Swordsman - Sword
Fighter - Stick
Turtle Hermit - Rod
Crane Hermit - Fan
Dark Warrior - Claw
Shadow Knight - Axe
Dende Priest - Scroll
Poko Priest - TBA
Ultimate Majin - Trumpet
Grand Chef Majin - Food
Plasma Majin - Drums
Karma Majin - Mask