I've always prided myself on good etiquette, but your question perplexed me. I've never heard that only certain people are "appropriate" hostesses for bridal showers. I say nonsense.
Anyone who is generous enough to host your shower is a wonderful person and I see no reason to turn them down. Go for it.
Some people would say it's wrong, but if you and the people invited do not care why not. She could help plan the shower with one or more of the bridal party. Mother of the bride hosting an bridal shower, is not as bad what a lot of couples do.
Today some brides hold their own showers, mother of the bride or groom look really good next to that. Today couple tell people to give them cash, again a lot worst than mother of bride/groom hosting an shower. I had mostly family wedding.
I had an family shower from my aunt and my mother in law. There was no none family members invited to these showers. I been to showers where the mother of the bride/groom gave showers.
Or been involved planning with the bridal party. Yes she can. If anyone has an real problem with that, they can always say no.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.