Connection between 'proxy', 'pronumeral' and 'pronoun'?

I was thinking about the words pronumeral and pronoun; I realized they both share a prefix, and are both proxies for numerals and nouns. I was wondering if there is any connection between the words since proxy also begins with pro. If proxy is unrelated, is there any reason for the two words to start with pro?

According to the Oxford English Dictionary, one of the senses of the prefix pro- is:

Prefixed to nouns to form nouns and occas. derived adjectives with sense ‘deputizing for, standing in place of’.

This is the case of pronoun and pronumeral. The etymology for this particular sense is:

in these, Latin prō- in the sense ‘for’, ‘instead of’, ‘in place of’, was prefixed to a noun, apparently originally in prepositional construction, as prō consule (one acting) for a consul, afterwards combined with the noun, as prōconsul proconsul n.1; so prōflāmen deputy flamen (compare flamen n.), prōmagister deputy head (compare magister n.), prōpraetor propraetor n.; also in a few names of things, as prōnōmen pronoun n., prōtūtēla deputy-guardianship (compare tutelage n.).

Now, what about proxy? The OED says that it was originally a form of procuracy, which is

the office, action, or capacity of a procurator (procurator n.1 1); management or representation on behalf of another.

The etymology ties this to the Latin prōcūrātio. EtymOnline provides some context into this, citing:

c.1300, "bring about, cause, effect," from O.Fr. procurer (13c.), from L.L. procurare "to take for, take care of," in classical Latin, "manage, take care of;" from pro- "in behalf of" (see pro-) + curare "care for" (see cure).

So, proxy, pronoun and pronumeral do all share the same prefix pro-, although proxy came about its pronoun through procuracy.