Yes, the sprayed paint should dry down flat. If it's dryng with an orange peel look, then that is likely a problem with atomization. The paint not atomizing can really occur because of any number of reasons....wrong tip, wrong fan size, wrong pressure setting, wrong temperature of material, wrong temperature of the air, wrong paint, wrong primer, paint applied too heavy, paint not applied heavy enough, overspray, etc. Were the doors laying flat when sprayed or upright? Sometimes if they are sprayed upright, gravity can actually make the paint sag a little bit and that may end up looking like an orange peel. You could try to sand it out. You can paint over the oil based paint with latex, but it needs to be dull and you may even want to reprime.

In a "high durability needed" area like that...I can't imagine NOT priming.... * Scuff-sand thouroughly with ~ 100-grit paper. 120 is TOO fine to be of much use here. * Sand until the scratches are minimized to your satisfaction. Get every molecule of dust wiped off. Here's a statement that may surprise a few out there!!! >>> In THIS case...I'd apply THREE coats of the Oil primer, about 2 hrs. apart. >>> Reason?: * You'll be building a lightly sandable layer as a last "polishing-off/filling" opportunity b4 the CC. * If you can, wait until next day for primer-coats to harden-off. The wait makes this last "fine-tuning" sanding go easier. You're gonna lightly sand this primer-sandwich. * Think of sheetrockers doing their last sanding b4 painting. NOW...you've built the ideal base for your CC to show its absolute best. Stir the CC thouroughly, scraping the bottom and sides as ya go, using slow/lifting motions. Preferably, have it machine-shaken. You may have to strain it through nylons, or a disposable paint-strainer. If it doesn't smell "sour", you're golden! Faron PS...DEFINITELY...TWO coats of CC!

If they are both acrylic paints, it should stick just fine without a primer.

Guardz works fine - no specific need to use an oil based primer if fumes are a concern. Sanding the walls is a good idea, then guardz, then a little more sanding if necessary, skim, skim, skim again if you want it perfect, prime and finish with premium quality materials. Zinsser's Kitchen and Bath paint seems to work well in high humidy environments. Or If the walls are not painted with semi-gloss or have torn drywall paper showing, simply sand the walls and start skimming. Priming is usually not necessary over flat or low sheen paints. Do use a high quality primer over skim coated walls prior to painting with 2 top coats.