My son has one, he doesn't have CF, he actually has Hemophilia and we access and infuse clotting factors 2x/week using it.
Let me see if I can answer your questions:
1) How big is the needle they use for ports? It is a bent needle and about 1/2" long, but you don't really notice it.
2) Do ports hurt when they put the needle in? At first it will hurt some, but over time the skin 'toughens' since you are using the same small patch of skin every time. I can tell you my 7yr old would rather have us use his port than his hand/arm any day of the week.
3) How big is the hole? Are you referring to the port itself...his port is about the size of a nickel, but it is fully under the skin so there is not a 'hole'. The incision to put it in was maybe 1.5" long.
4) Does it pop out of your chest or is it under your skin? Under the skin, some put below the collar bone, I have heard of women getting it below the breast so it is not visible, my sons is about 1/2 way down his chest on the side. Dr said it was great for a boy as it reduces the chance of getting hurt (vs a shoulder).
5) Does the port hurt or get sore if touched or bumped? Not heard him ever complain, maybe someone here with one can answer.
6) Is the port a inconvenience in any way? Compared to a PICC or an IV, no. When they are not being used it is fully hidden. The only thing is that with CF if you are not using regularly (I hope you aren't) then you have to flush with saline every so often. You also have to have abx before dental work (quirky but not a big deal).
7) Can you see the port if you're in a bathing suite or see it pop out through a shirt? Swimsuit would depends on where it is, but it is not very noticable and it should not be seen through a shirt (unless it was VERY tight) and it would just look like a little bump, nothing anyone could identify.
8) How long do ports last? Normally a long time, sometimes things go wrong, but they can last for several years w/o any issues normally.