Do you have any information as to whether these are being used at all on the Librem 5?
On mine they are each 4MB but they read as zeroes. Maybe that’s because of some security setting. Or maybe they really aren’t used.
There may be no harm in exposing these two partitions read-only. However over USB there may or may not be a way of enabling write access. And if there’s no way to enable write access then that should stay so.
I don’t think it will fit. That’s not to say that it couldn’t be slimmed down but that could be a fair bit of work.