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QUESTION: So what do wall of these additions actually mean or signify?

[name] Senpai, [name]-ama, [name] onnesamma, [name]-chan, and [name]-san.

Or if anyone has any additional ones, please share and explain.

ANSWER:
(name)-san is the same as Mr or Mrs. It's for someone you respect or want to convey politeness.

(name)-sama is like Lord or Lady. It conveys a lot of respect, but can be overdone. Mostly it's used to refer to customers, these days.

(name)-chan: ONLY use this when you're referring to someone who is very close to you or who is obviously lower than you in station by a long bit (an adult referring to a young student, for example).

(name)-kun: generally used to refer to men. Implies at least some bit of familiarity with that person.

(name)-sempai: an upperclassman or senior co-worker.

(name)-sensei: teacher or doctor

(name)-oneesama: that's not really used. Oneesan is older sister, and you can sometimes use it to refer to younger women (say 20's or 30's) you don't know. Oneesama I've only ever heard used in anime. Similarly, oniisan is older brother.

Finally, (name)-dono: a very antiquated form of san. Again, only in anime or video games or literature.

Maybe we should specify that you start out using last names, since that's most common. First names indicate a certain degree of informality.

When in doubt, use last names.

Very possible. I think it's also something that's not used in friendships but more for classmates and coworkers, if that makes sense. And I have heard it used in reference to women... but only in a work setting in an anime.

Close friends generally drop all titles, but some gals I've met just seem to like being called "chan"- maybe because it makes them feel younger.

In regards to titles like "Oneesan" and "Oniisan", this 'family titles' thing stretches to all ages. A much older man you don't know could be called "Ojiisan" (grandfather), an older woman might be "Obaasan" (grandmother). Just be careful not to slip up with "Ojisan" (uncle) and "Obasan" (aunt) or you might accidentally call a middle aged person old.

Times to use this sort of nomenclature is either when referring to someone you have just met and may not talk to again (such as small talk at a bus stop) or telling a story to a third party.
For example:
先日に知らないおばあさんが僕に「すてきな天気ですね」と言いました。
The other day, an old woman I didn't know said, "beautiful weather, isn't it?" to me.

It's a little casual so if you aren't talking to your friends, you might try to use polite language. 方　(kata) means 'person' and will never offend.

About kun. Always ok for younger male acquaintances, alright for a male subordinate at the workplace. There are some women who want to be called kun but it's pretty unusual and you should make sure they're ok with it first. Similarily, calling a man or even a boy "chan" might be offensive. Baby-age children are almost always chan, but once they hit first or second grade it's best to switch to kun for little boys.


PS- Just for funnies. "-tan" is a variant of "chan" that's super dooper cutesy, used largely for anime mascot characters. Also, you'll only ever hear it in samurai movies and period pieces, but "-dono" means "lady" or "lord". No one uses it anymore.