Alrighty all.
I want to thank you for your tips and guidance.
I am smarter than I thought I was, yet still pretty dumb, because I attempted to remote in to the client in question and it worked. Though I couldn't ping it, I could remote, proving my Client VPN can share resources between the subnets,
(I had previously allowed remote access on the PC in question)
The ping issues must indeed be the client firewall configurations. So I am in business. I guess I should have tried the ultimate goal before thinking I had an issue.
I might still enable Ping through group policy when I roll out Azure AD but for now I am good.
Thank you again for your help.