Can a wizard copy spells in his spell book that are above his level?
I think so.
Can a wizard copy spells in his spell book that are above his level?
I think so.
Yes. He just can't cast them.
+1 Flaming Icy Burst Arrow (there might be something on stacking elemental weapon strikes.)
wondrous item probably.
1) Yes.
2) +1 flaming icy burst so long as your GM allows it. There are no rules preventing this.
3) Quivers are wondrous items. The one for which you are thinking would be a command word based quiver that would enchant an arrow.
I would direct you to scabbard of keen edges for an equivalent example. Keep in mind, this is 16,000 gold for an item that can cast a 3rd level spell on 50 arrows, three times a day. The spell would last 50 minutes (CL 5 and 10/min a level).
If you wanted something similar for Magic Weapon, you'd either have to use it on the bow or use Greater Magic Weapon on the arrows (since only Greater can work on projectiles). The nice thing is that you could easily take the same price for the Scabbard and say your quiver casts a different 3rd level spell three times a day (but with a 5 hour duration on the enchanted arrows given the GMW spell is 1 hour / caster level).
A bow which shot Deadeye's Arrows would be a magic weapon and a rather pricy one requiring the ability to, on command, shoot a level 1 spell. You're better off making a wand out of the spell, but then you'd need to be a druid, oracle, paladin, or ranger to actually use the wand (or pass a UMD skill check).
A bow that cast magic weapon on itself will be far more expensive than just buying a +1 bow. Or a wand of it (which is only 750g for 50 charges, though you need to have someone who can use the wand).