In my opinion, Lindbergh was a space pirate while still possibly being a mink. Here’s some of the reasons:
1-Check out this particular “meter” design that appears in Lindbergh’s jetpack and also in various space pirates chest.
Of course, we don’t see one on Lindbergh’s chest, but that’s because he is wearing clothes, similar to one of the space pirate which we can conclude at least this device is not worn outside the clothes but is attached directly on the body.
2-Most space pirates that we saw so far in Enel backstory are at least in mink like features though some are weirdly shaped, they are by and large similar to minks – humanoids with animal features. Also space pirates seem to be quite technologically advanced too with one of the cover story showing a chimney like machinery that seems to produce steam, possibly the technology behind jetpack.
3-In one of the cover story page, the space pirate seems to channel electro from his weapon. Something similar to what mink could do.
4-Lindbergh seems to be an inventor with quite technologically advanced weapons that we never see much elsewhere. However, the mink tribe and also their hometown on Zou doesn’t seem to incorporate any form of technologically advanced knowledge and simply putting Lindbergh as only a mink seems weird here.
5-Also, based on his name reference, Charles Lindbergh was a famous aviator. In 1927 he became the first man to successfully fly an airplane across the Atlantic Ocean. The closest thing to airplane in One Piece world that we have seen are of course various flying ships such as Enel’s.
Assuming Lindbergh is a space pirate indeed, there’s some speculation we could make:
1-There’s a way to travel from Space to One Piece world. So far we have seen Enel’s Ark Maxim but it is being destroyed. This could signify the return of Enel if there’s a new way. Yes ENEL HYPE IS REAL.
2-Minks could possibly be originally residents of the moon/space.
3-Monkey D. Dragon could have been to the moon and met Lindbergh there.
4-Perhaps this explains why minks are at full power when full moon other than the typical werewolf kind of story that we know
5-Lindbergh could have joined Revolutionary Army because he wanted to meet his fellow counterparts
*Theory by boyplunger56