You guys are both so cool for working this hard on stuff, just wanted you to know.
As far as your mod, I can see this being a great addition to vanilla, the vanilla tech-tree generally being somewhat of a mess, but do you really think such an expansion is really necessary for VP? I mean the Ancient era techs are already heavily modified and far more heavily linked together than they were in vanilla.
Anyways if you're going through with this I figured I'd give you some general thoughts on it, or at least some things that I think it would be helpful for you to consider.
First of all, VP changes how resources are unlocked, having them show up on the first tier of techs instead of just being visible from the start (might be some clashing if you move techs around).
Second, VP have settlers moved to pottery, this doesn't necessarily mean that much of a settler delay in general, but if pottery isn't a first tier tech in your mod, you're going to be forced to pretty specific tech-paths.
Lumbermills and marsh-clearing have been moved quite a bit as well, and keeping them where they currently are would probably be a decent balance-decision, at least consider it.
Most resource-improvements unlocks on either tier 1 or tier 2 techs(with all tier 2 techs having either 1 or 2 pre-reqs), this is a conscious balance-decision based on existing pantheons as well as the new happiness system, exception to this is resources that are stuck under features (forest/jungle/marsh), they are in general unlocked later and most of them are tuned to provide an early-game advantage to compensate (and there is the herbalist building to further improve them prior to chopping)
Masonry and Construction got their names flipped (still not exactly sure why, but that's how we roll) and Sailing/Writing are both classical era techs now.
Don't take this as me trying to shut your creativity down, I'm just trying to be helpful. Also if you're talking about just the base part of VP (not the overhaul-patch) I think everything I just said is invalid and you can just ignore it

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Either way, good luck with your project.