3) you are so lucky! I get frequent nosebleeds in winter due to dryness. Initially it just feels like a very insistent, copious runny nose. It doesn't hurt in any way, it's just annoying, and you have this faint but slightly gross blood tang in the back of your taste sensorium.

4) go have the coffee. If the person in question is flirtatious, or seems to be hanging on your every word, or seems to be trying to impress you (hopefully in ways that are not douchey -- I mean by being considerate and witty and so forth) then it may, indeed, be coffee. (Even if not, it might still be coffee -- but any of those ones are pretty good indicators.