No such thing as a dumb question... Answers are another matter! 
Paints, hmm, you will get as many, if not more opinions than there are modellers.
Old school, as characterised by Verlinden, was base coats in enamel, then dry brushing in lighter shades of base coats (adding tan not white) then enamel rust & graphite pencil highlights. Leave it a day or more & you were good to go.
Old School enamels could take hours/overnight to be touch dry, then days to fully cure.
Assuming your seat base coat is acrylic, which is touch dry in minutes/hours, but can take a day to fully cure... (always leave as long as possible) applying thin oils on top should be ok.
Caveat: the key point of using oil paints, especially in pure form for figure painters, is they have two usefull properties.
A: They can be applied thickly, or very very thin, translucent layers, you build up layers & blends slowly.
B: They can take weeks to dry, helping with the above, blending, translucency, etc.
Assuming you are using those oil pens for washes as by MIG, or the Airfix washes (enamel) etc, then they 'may' dry a lot quicker, but leave as long as possible.
The only way to be sure is to do a test piece at the same time, same base materiel, primer, top coat & same oils dry brushing.
Perhaps the underside of a tank, or interior of the aircraft wing? or a failed build/junkyard/range hulk as a tester.
Then use that as a test piece for trying painting techniques, handling and varnishing.
Once you gain experience with the materiels you are uing, you will be able to gauge your working better.
Consensus of modelling opinion (ha! as if, see above, 
) is primer, acrylic, gloss acrylic varnish, pigments or oils, leave for ages!
i.e., paint down, protect your paint layers with acrylic varnish, then weather with pigments, emamel washes or oils...
Many modellers report problems trying to apply 'hot'/lacquer or enamel based varnish on top of acrylic finishes, especially if applied too thickly as they can react, especially IF the base coats are not fully cured.