Hmmm... they way I see it as possible is:
- Quivers of arrows are items [QUIV]
- Bow and certain arrow is also a weapon [B&A]
- Bog-standard bow is a weapon [BSB]
When the user equips the BSB it calls a common event into play that checks to see which QUIV you have and asks you which one you would like to equip. You choose one, which then equips the corresponding B&A and unequips the BSB.
If you set each QUIV to be the equivalent of 5 items, then you can have a common event checking to see how many QUIV you have, and deducting one every time you have a battle (this common event could be called at the end of each battle). If you want to go the whole FF hog you could have a battle screen pop up after the battle saying: You have X quivers left. When it gets to 0 quivers left, then your QUIV could be unequipped and the user then has to change to a different QUIV and hence a different B&A.
The battle animations are all weapon-dependant, so yes, it is possible to change them.
Which maker do you use? I can't remember if you're the 2K3 camp or the XP camp.