Gotta admit I am not totally sure if I got half of this straight... as I struggle to make sense of a few of your sentences...
What I can say is that there are clear crossovers of ToP in ZL... the otherway around we haven't seen anything though.
The 2nd male you saw is the Protag of ToP, so that's one crossover right there.
I did mention crossovers on several occassions, so I obviously agree that there is a connection to ToP... but that is wholy one sided.
The technology and civilization in ToP never advanced beyond the medieval (maybe early victorian era), there are no guns, cars, planes, ruins of - / skyscrappers or anything else indicating an advanced civilisation/technology like in ZL.
...hmm after checking the Patreon I Quote
Zombie's Retreat takes place in the same universe as my current/main project, Town of Passion! Expect some cross over as well as story references from that project!
so we might not be in the past of ToP but it's future... ZR might be the world of men AFTER ToP story.
And the Godess of Lust just tries to strike again useing the artifact for her plans.
Dr. Cherry says that there is a strange power in the MC of ZL (in his seed to be exact), which she theorize is the reason for his immunity. (maybe a direct descendent of the MC in ToP)
We don't know how the goddess of Lust actually brought an end to the world of men in ToP aswell... only that it happened and that Minerva sealed some kind of hope in the city of Valencia (which is connected to the MC). In the Mansion she used trickery to make the lord kill his daughter and the Maid the entire family in hope to revive her again (several notes/diaries around the mansion).
In ZR the report of the last scientist says that it was the 3 scientists we already learned about in the Powerplant that experimented on plants, animals and humans... and that they noticed far to late that something was amiss... The one called Cullen Lindley was obsesses with Project Lunar aka the artifact... there is atleast a chance that he was manipulted by the goddess of Lust, some of his reports seem... disturbing... he later left for the town to experiment on the Rifts and energy. The one called Adam stayed behind and experimented on the mutations... creating these plant monsters.
He is stateing that the stone once created men like monsters and is an artifact of Legends... maybe the holy grail... the philosopher stone or something the like.