Better than I could have done it, for the most part! Just a few ideas.

When the old Frosch is summoned, in the opening first, he is to come with his Schaar, you called it his "band." I prefer "host," as in
Holy, Holy, Holy Lord God of Hosts.
A green host of frogs.

Yes, Joe Offer, this is a timely satire of spring commotion!

I am no historian. What say you all, who know your European history?
I think this satire predates Napoleon, shame on me for being uncertain.
And what were the German principalities troubled with before Napoleon?
Waiting for winter to end and spring to arrive,
that could be a metaphor for a time of deprivation and strife.
Nobody blames the Musikanten for raising their voices in hard times.
Then Spring comes, with life and growth and abundance,
and the King says, Enough already, you can stop hollering for attention....