Well, I made it pretty far through the process of purchasing a resale unit at Marbrisa that had day use privileges granted as part of the original deed, which was a Grand Pacific originated deed. I saw a copy of the Escrow Owner's Addendum stating such.
The word from the powers that be at Grand Pacific is that day use privileges do not transfer unless the ownership is transferred to a family member.
Further, the COO of Advanced Financial Company, which I assume has some type of role in this, also said:
"In regards to Day Use, it’s currently described in the signed document as: “Day Use” is a special benefit conferred upon Incentive-Partaking Owners under which you, as such an Incentive-Partaking Owner(s) may use the Grand Pacific MarBrisa Resort….”. Unfortunately, since in this case the special benefit was provided to these specific Owners, Day-Use at this time is a non-transferrable special benefit."
Not the outcome I was hoping for, but I hope what I found is helpful to others who may have the same question about getting day use to Marbrisa in the future.