The other factor I would consider is what other showers might be out there. When I got married I had 3 showers - a friends shower, one with work colleagues and one with a woman's org I belong to. One concern is that if there are other showers / celebrations - it may be everything in total that is taking things over the top.
If she is feeling like it is too much - then it probably is. I would have a chat with her to talk about it - and see if there is a way to know how special she is to so many people, in so many ways - without having a so many events - you have listed 5 - add a wedding, a rehearsal dinner perhaps, perhaps a post wedding reception in her home town, showers by other orgs/ groups - and that is a lot of attention.
You are a good friend for wanting to make this so special for her. Good luck.