Our first basenji puppy was born 10 Nov 2017, we brought her home 8 Jan 2018, and she began her first heat cycle—the heaviest bleeding lasted 2ish days—around 1 April 2018, so she was not yet 5 months old when it happened for her.
Our contract with the breeder stipulated we have her spayed at 6 months (I know, I know Sally; we got our second B from a different breeder and he is intact with no plans to change that), so it was kind of unfortunate that she had to deal with it. It seemed to really bother her and ran away if a drop of blood fell on the ground while she was walking, although there was such a small amount of blood that I wasn't 100% sure it was estrus. Her rear end became engorged, almost to the point of obscenity, and I kept her away from other dogs, as 1) no puppies for my too-young girl, and 2) she went from super-playful to permanently annoyed, then back to super-playful once it was all over. The engorgement lasted a month or more, but everything went back to normal eventually.
So: it's definitely an experience for your girl, but considering the fact that I wasn't sure she'd been in heat at all until after her 6-month surgery and her vet confirmed that she had recently gone through a cycle, it's really not going to be as bad as you think it might be. I don't have much to offer for your questions about long-term things (other than intact males are comparatively easy to deal with, in my experience), but the actual season really isn't a big deal.