My two concerns: the list is not combat-oriented whatsoever, the desire to sit and shoot will be difficult to resist even in scenarios which require close-quartered fighting; the other being the low number of units overall coupled with the low defense of the Rangers. Let me know any ideas you have on the list!

Warband 1
Elrond on horse
5 Rivendell Knights

Warband 2
Erestor
6 High Elf Warriors with elven blade
4 High Elf Warriors with spear and shield

Warband 3
Legolas Greenleaf
10 Mirkwood Rangers

Looks pretty combat oriented to me. I think it could work, I have little experience with elves. Do the Knights and Rangers get their army bonus if they are allied?