There are functionally quite a few 3p. pronouns. hic/haec/hoc etc.; ille/illa/illud etc.; quis/quid etc.; is/ea/id etc. are functionally pronominal in many ways. They are actually adjectives which can function as nouns/noun phrases when standing alone. However, I would warn against using these in the sense of he/she/it. Each of the above examples has a different function, but Latin often omits a subject noun phrase. For example, you are much more likely to see 'puer est' than 'is puer est,' or 'ille puer est,' or really anything else. The he/she/it is usually just assumed based on the preceding sentence(s). For example:
'Marcus puer est. Iuuenis est.' = 'Marcus is a boy. (He) is strong.'
I think some medieval Latin writers used ille/illa/illud in the sense of he/she/it, but that may be a false memory.
Here, there's no noun in this sentence, so it can't be "this".
It must be "he" (even if the verb doesn't need the subject-pronoun)
If you have a sentence with a word as a subject (=nominative, in a sentence without "to be", being a copular verb.), it means that you can't have 2 subject, and it can't be "he", so it's "this".
Normally, I believe that this "this" is found close to the name it's supposed to qualify or modify: "Ille vir".
"Is" is demonstrative (singular nominative) in this case:
"Is vir" = this man.
"Is vir" can't be "he man" as there's no verb, so it's "this".
If you have "is" as a verb (ĕo, ire), it's to go.
"Is ad ludum".
You see it, because it can't be modifier for a noun.
And it's can be the subject-pronoun "he".
It can be only a verb here, no other verb.
That's right. Latin has very flexible word order. The "who-does-what-to-whom" is conveyed mostly by morphology (word forms) rather than syntax (word order). Typically the verb goes at the end of the clause (subject>verb), but some Latin writers regularly put it in the middle of the clause (subject>object). :)