Can I use Minoxidil and Propecia after using caffeine shampoo and liquid?

Great question, No, it shouldn't be a problem using Finasteride and Minoxidil with or without caffeine shampoo. But It is critical to see for a detailed evaluation, photos and follow-ups to an experienced and local hair loss specialist in your city or state. Good luck. 

No problem in using a shampoo containing caffeine (although keep in mind it may or may not do anything). As far as caffeine liquid goes, if that is being applied to the scalp it should be done at a different time than minoxidil- otherwise you will dilute the minoxidil and change the absorptive properties of the skin.

It is fine to use Propecia and Minoxidil together in conjunction with a caffeine shampoo. They won’t counteract one another.

I don't see what minoxidil has to do with your choice of shampoo. Use minoxidil at night after a hot shower for best results and leave it on over night