Care and feeding of skid plate bolts

.... embedded in the chassis or the subframe carrying engine/tranny

Blue loctite vs antiseize compound?
The fasteners are swimming yearly in a sea of salt used to combat snow
and ice in winter months and I've lost one attamchment point
lately (vibration? hitting something on the roadway with the fastener's
head. not sure).

Lots of swearing comes from servicemen upon changing oil and coolant
removing the rusting skid plates and the nuts.

I got some stain less steel bolts (and nuts with serrated seats) but am
wondering what to do about the bolt threads before the new ones get
welded in.

Which is all the more important if I'm to change oil myself next summer

tnx