I'm planing on making the map coasters and wondered if you can use

Your best bet might be resin. I have a piece with my daughters hair in it and it's been 38 years going strong. I go to this link often.

https://www.google.com/search?q=best+resin+for+making+coasters&rlz=1C1BLWB_enUS700US700&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjh4pGn3OrTAhWl3YMKHVT6Dq4Q_AUIDCgD&biw=1024&bih=714

I've made a bed tray and decopauged pics on, and then finished with a two part epoxy which worked great because then I didn't have any brush marks and it self leveled...use it with hot coffee and tea with no problems...also I finished a table with polyurethan, and no problems with heat...on Wikipedia it says most aren't, but I'd read can...

I've made a variety of coasters with different papers and have always used Mod Podge with remendous success. It is unaffected by the heat and they can be wiped clean with a damp cloth. No dishwasher.

I have used several things: Mod Podge, spar varnish, resin. Are these coaster for use with coffee mugs or are they for hot pots on the table?

I have used both Mod Podge and Marine Varnish. The varnish holds up better.