The following weapons have been confirmed: Magaton Hammer, Hookshot, bombs, Deku Nuts, Deku Sticks, and bow and arrows.
A Longshot may also be available later in the game. Don't expect to see a
slingshot seeing that Kid Link can now carry both the bow and the
Hookshot. Bombchus may have been neglected this time around, although
seemingly useful, they weren't fully utilized in Ocarina of Time. Other
weapons which will most likely be obtainable are the boomerang (has there
ever been a Zelda adventure that didn't have a boomerang), various magic
spells (after all, you can buy green and blue potions capable of restoring
magic) and magical arrows (fire, ice, light). Hopefully there will be some
other surprises as well. Oh and upgraded carrying capacities to thiings like
bombs, nuts, sticks and arrows are a given.

Some weapons can be used while Link is performing special actions such
as riding Epona and gliding as a Deku Scrub. While on Epona, Link can use
his steady eye to shoot arrows at moving targets and Poes. When gliding,
Link will have his trusty Deku Nuts readied in case any baddies try and
assualt him before he lands.

In Ocarina of Time, Kid Link and Adult Link could share some inventory,
but many items were specialized for each character. This will be the case
for some items in Majora's Mask as well for instance, it appears that ONLY
Kid Link will be able to use both bombs and arrows. This may effect other
invetory as well