You can see how the mainspring is bending backwards there. It really should never bend up like that. It works, I guess, but it drives me crazy.
By golly, the stock shape doesn't look THAT horribly bad. They did manage to get the wrist to flow nicely with that lock. And definitely don't try to thin the wrist down.
I can't tell how much drop it has. I'm sure more than it should, but maybe not too bad. If you can get your cheek on the side of the stock and actually see the sights, I guess you're good.
Triggerguards. The top one would, honestly, look rather out of place on the gun. It's something that you would be more likely to see on something Austrian or Bavarian or somewhere south of the Main river. Your stock... not so much. I think the open guard you have would be much more suitable for the stock, though it could use a little reshaping.
The Rococo shaping on the upper triggerguard is somewhat later in form (at least on German guns). When you see this type of hardware UNengraved, it's a pretty good sign the gun is post 1770. And definitely doesn't go with bulbous ramrod pipes. I suppose the buttplate is already inlet, and it's probably the one that matches this triggerguard.
If it was me (and obviously, it's not me), I would use the open bow triggerguard, your choice #2 rod pipes with the skirt filed to a nice pointed shape, and for the buttplate... I would hunt and see if I could find one of the blank brass buttplates that they apparently don't make anymore, and just leave it a long square tang to cover up all the curvy inletting for the rococo buttplate. But again, that's me. Yes, you will see German rifles with plain long square buttplate tangs like that. Don't even need flats or filed rings.
You may just be stuck with the buttplate you've got. There ain't much choice anymore.