I have strong ideas about this… I apologize if anything I say is offensive! Incoming rant!
First off, I think kids should get their own names. I really, really dislike naming kids after relatives (alive or dead) as a way to honor that relative. It’s a lot of pressure, it can make things super confusing… my cousins named their first daughter after the husband’s mother, and now we have to call this poor little girl by her first AND middle name (a total of 5 syllables) just to tell them apart. It’s obnoxious. I see stories all the time of fathers/grandfathers and sons/grandsons getting their mail mixed up because they all have the same name, and it can even lead to mistaken identity theft. Just give the poor kid their own name! Then you never have to deal with “well, which Robert are we talking about here?” There should only be one Robert. Your name is your identity, and it can be really hard having to share such a huge part of your identity with somebody else.
As for the actual mechanics – my husband is Vietnamese, and he and his siblings all have a first name, 3 middle names, and a last name. In the case of my SIL, her first name is actually two names hyphenated together, and she only uses the second of those two names because the first half is her mother’s name AND HER AUNT’S NAME. Yes, Mother-In-Law and aunt-in-law have the same first name. It’s awkward and confusing and I don’t blame SIL at all for choosing not to use it as well. So there’s a real-world example of a person being named after another person and actively rejecting it! And if that’s not bad enough, she runs into the issue of people who want to call her by her legal name (teachers, doctors) and it makes her really uncomfortable having to explain. It’s legitimately a form of identity crisis. If you’re setting up your kid to have to explain their name a million times over the course of their life, you should really reconsider. For that reason, the name you’re going to call them every day should be the first name. All the people I know who go by their middle name (either because that’s how they were raised, or because their first name is dreadful) just let the first name fall by the wayside and effectively disappear, so what’s the point of putting it there in the first place?
Multiple middle names can be really tricky US. You can put them on the birth certificate, and even on the passport, but they don’t really fit anywhere else. My husband uses the three initials for his drivers license and work ID, but there are SO MANY forms and questionnaires where there’s only room for 1 middle initial, so he just uses the first one. It’s an issue every time we fly somewhere because your ticket has to match your ID, but he can only use his first middle initial when booking the tickets even though all three middle names show up in full on his passport. Essentially, there’s no point to his extra middle names. They just complicate things.
Finally… if you have heaps of people you want to honor, and you can’t leave any of the names out, just don’t use them in the first place. If you’re trying to honor everybody, essentially you’re honoring nobody. There’s no point if all of the names are equally important and everybody is included. It just seems so bizarre that you either have to have a half-dozen kids to honor everybody you’d like to, or give each kid a cumbersome number of names. What if you end up only able to have one kid? Just raise your child(ren) to know who their relatives are/were, and to respect the contribution they made to the family, and call it good.
End rant. Like I said, I have strong feelings.