"I want them all for myself!"
Translation:Le voglio tutte per me!
"Ne" has the connotation of being part of group. Your sentence has a meaning like "I want part of all of them for me."
BTW, I think "per me" is fine, but a better wording would be "per mi stesso". The "stesso" makes it closer to "myself." E.g. "her/hisself" = "si stesso". "Themselves" = "si stessi/stesse"
'gli' is not a direct object pronoun. 'li' and 'le' are.
here is a web page that can help you. http://www.uvm.edu/~cmazzoni/3grammatica/grammatica/
It is correct, but "io" is necessary only in certain situations. If "io" stands in a sentence, it highlights "me" and not another person already mentioned (or may not). here is a generic example situation:
Mamma: Chi ha mangiato tutta la torta? Paolo: Non io, non io! E' stato Maurizio! Maurizio: Sì, io ho mangiato la torta, non Paolo.
In the previous sentences "io" is stressed and becomes the most important part of it. If in the previous situation "io" wasn't written, the text could be translated in different ways.
These are small nuances but they are pretty important. In Hungarian, for example, it is also important where you put a certain personal pronoun, as its meaning may become totally different. Thank God such a thing doesn't happen in Italian. :)
"ne" like other object pronouns precedes the verb. "ne voglio tutte"
here is a web page that may help: http://www.uvm.edu/~cmazzoni/3grammatica/grammatica/
Brace yourself. It is a little confusing:
Loro (subject): they
Loro (object): them
Loro (possessive): their
Loro (indirect, the same with "a loro", but sometimes we use the singular informal gli/le instead of it): [to] them
"Loro sono i miei amici", they are my friends
"Ho dato [a] loro le chiavi/ho dato le chiavi a loro", I gave them the keys
"Ognuno di loro sa cosa intendo", everyone of them knows what I mean
"La loro casa è bianca", their house is white
"Di loro" doesn't exist as a true possessive form in the sense of "owning" as you can see, because "loro" alone already does that. Note that "loro" as an object of a verb isn't frequent, because we mostly use other pronouns instead (li, le etc), infact you see that I want them all=le/i voglio tutte/i.
To add some information (not that this topic needs it but you may find it interesting): when you don't know someone's gender or when it doesn't need to be specified at all, you don't use the "they" form like in English, you would probably use the "persona" form (consequently using the feminines that "persona" requires), unless you have something like "qualcuno, nessuno etc", but since this is not fixed like in English, there really isn't an official way to express it. Just don't use the plural!
I really hope you found this helpful! :)