Many times the expiration of a drug is not firm and they can often be used beyond the expiration date, but it is still always safest to follow the oficial guidelines
The key question is whether the Demodex is causing a problem or not. Demodex is often found in biopsies. I advise working with a specialist to determine if this finding is relevant or not. We don’t always treat this - it depends on the specific clinical scenario.
Leave-in conditioner will not hurt the use of Rogaine. Procapil should probably not be used simultaneously with Rogaine as it will dilute it. However using many therapies at once to get the maximum benefit for your hair is actually a good thing. All the studies show that using several therapies...