Zero-gap stem (FSA Afterburner) inverted installation
I'd follow your option 2. The labels on the faceplate and body of the stem appear in both orientations, implying FSA designed it and labeled it for use either way. Given that, they must have intentionally only put the &quot;no gap&quot; label in one place for use in both orientations.
Grease all the bolts, unless instructions say not to, or they are already lubricated/protected by another method like threadlocker. Aside from lubrication, grease or threadlocker creates a physical barrier between the threaded items, reducing corrosion.
Regarding threadlockers, there are various types:

Added liquid chemical threadlocker which cures to a solid between opposing threads, in theory preventing movement and loosening. Oil/grease can interfere with the curing process. When removing and reusing the fastener, the old threadlocker must be cleaned off and fresh threadlocker applied.
Preapplied malleable solid mechanical threadlocker. This works by remaining malleable and dampening vibrations, thus preventing movement and loosening. There is no curing process, so it should be at least somewhat compatible with oil/grease. When removing and reusing the fastener, the existing threadlocker is reusable as long as enough remains in place.
Preapplied &quot;dry&quot; chemical threadlocker. This is basically just liquid chemical threadlocker encapsulated in tiny beads which break open when the fastener is tightened. Oil/grease may interfere with its curing process, although Henkel/Loctite says its &quot;dry&quot; threadlockes are &quot;Solvent/chemical resistant - all oils (motor, ATF), water, glycol, petrol, diesel&quot;. Like liquid threadlocker, when reusing the fastener, this needs to be cleaned off and fresh threadlocker applied.

Here's what I do:
a) follow the instructions for the part if available.
b) always use grease/antiseize/threadlocker of some type on threaded fasteners (unless instructions say differently).
c) if I feel the amount of pre-applied threadlocker is not enough to reach the full length of threaded contact, I may add a small amount of grease or threadlocker to the threads away from the pre-applied section. Just as with beer, one can assemble quite a collection of different types of threadlockers :)
Some references:
https://www.assemblymag.com/articles/85609-do-your-fasteners-need-a-preapplied-thread-locker
https://www.fastenal.com/content/documents/2014/08/Loctite-Threadlocking.pdf
https://www.henkel-adhesives.com/us/en/products/industrial-adhesives/anaerobic-adhesives/pre-applied-adhesives-sealants.html