Ok, speaking about war horns, I have an idea
I cut the sound of the Mirkwood's horn from BOTFA, when Thranduil calls back his soldiers from Dale; the sound is almost identical to the one of DOS, when the Guards close the Gate of the Woodland Realm.
I think that it could be perfectly used in many ways, for an enhancing spell, or, better, a summoning spell for Mirkwood (since I assume that the Woodland Deers won't be available anymore in the Spellbook).
This horn is specifically the one of the Kingdom of Mirkwood, and it's rightly different from the one of Lothlórien.
If this horn will be included along with the 'current' one (via different spells in the Spellbook), the horn of the Galadhrim (if this spell has not been changed), I think that it will be an interesting and smart solution to mark the 'right difference' between the Golden Wood and the Woodland Realm, and their respective units
https://soundcloud.com/diewalk-re/mirkwoods-horn(I already made the track directly downloadable from SoundCloud, as all the other ones; the other tracks, though, of Galadriel, Elrond, Sauron, Smaug, Azog, Thranduil and Tauriel are already in the precious hands of FG15)