I don't know anything different on this than that you are making this up.
My guess is you have not considered this before. Everyone must interpret the scriptures my friend. The point is to seek the guidance of the Spirit in doing so.
Here are a few examples of how horns are ruling offices/callings:
Psalms 92:10
10 But my horn shalt thou exalt like the horn of an unicorn: I shall be anointed with fresh oil.
Zechariah 1:21
21 Then said I, What come these to do? And he spake, saying, These are the horns which have scattered Judah, so that no man did lift up his head: but these are come to fray them, to cast out the horns of the Gentiles, which lifted up their horn over the land of Judah to scatter it.
The 7 horns on the lamb are servants of the lamb. You can believe that is made up if you wish and that somehow God consists of seven spirits... but that is essentially impossible to reconcile with the rest of scripture, and again would be your interpretation not supported by scripture, whereas I have given you some of my scriptural supports.