Does applying minoxidil at the face for beard grow can cause acne, ingrown hair, folliculitis and other "bump" related problems?

This does not work well for real hair growth on the beard area. It may cause what you are talking about, I really don't know and you won't until you try it. Many young men want to accelerate their beard growth and ask
about it. It takes age (genetic triggers which occur in family lines) so
if you want to find out when your beard will grow out, you need to find out
when your father or grandfather started to grow theirbeard. Hormones should have kicked in
nicely by the time a man reaches 18 but he must wait out his genetics
as hormone alone are not responsible for the onset of beard grown. Beard
transplants can be done when the young man is a bit older (over 25) if the
beard has not grown in yet

The folliculitis, bumps, and ingrown hairs you describe are most likely folliculitis barbae and are caused from shaving.  It is not the minoxidil (although that may make it worse since it is encouraging the hair to grow faster!)LAser hair removal of the beard hair, as well as shaving with the hair direction and several other topical remedies are all treatments that can be tried.  See your dermatologist for his or her current recommendations.