There are already religious components in Civ VI that increase the 'spread' of the religion, allowing cheaper Missionaries or 'passive' spread at greater distances, etc. That implies (to me, at least) that any 'real' ability or inability to spread a religion is immaterial to the game's modeling of it: a Native American Civ with a religion that includes a bunch of the 'spread bonus' components is going to be the Proselytizing Giant of the game., or at least a contender for the title.
As to Gold/Money, to me the big differentiator is in the ease with which transactions can be made, and that is related to a coinage, later a currency system.
By around 3000 BCE (early Bronze Age) in Mesopotamia and Egypt they were using standard-weight bronze or copper pieces to accurately weigh small objects in scales. These may represent 'proto-coins' and may have been used as such, but the archeological jury is still out - which is probably a good thing for us gamers, because that would put the first 'coinage' so early that it would practically preclude any non-coin system.
Between 640 and 625 BCE in both China and Lydia (western Anatolia) stamped or cast coins were being produced, complete with comparative values of bronze, gold and silver and inscriptions and designs on the coins. This is the usual rough period when Money is considered to have started, but a whole bunch of other things, including natural shells, manufactured beads, and (referring back to the top) weights of metal were also used. Unfortunately for them as an 'alternative' to semi-precious metal coinage, they all were replaced by 'real' money as soon as it was available.
Not saying that a non-money/Gold economy and/or value system can't be made to work, (Science Fiction, in fact, has explored several alternative systems, but the key word is 'Fiction') but except in very early or very 'niche' groups, it would be largely an artificial construct.