Greetings,
I have exprerience with puppy linux as a user.
I can achieve your goal of having expressvpn usable from the puppy linux ISO
You can reach me ia chat so we get started, or to answer any question you may have.
Regards.
I can integrate express vpn in puppylinux, gone through the project specification, so I am confident enough to deliver the project in timeline. I can start the work right away.