My final update I guess for this topic, but my new provider doesn’t offer shell_exec() for shared hosting 
They provide SSH access, it’s just that shell_exec() is disabled.
They have options as quoted… just not for shared hosting…
“You would be able to run this on a VPS or using the dedicated cloud hosting options where you can then manage the disabled_functions on the server to meet your own needs but that would be a more expensive hosting option”
I’ve checked and it’s a bit expensive for all I’m needing to do with Square, so I guess I’m gonna do without Square’s bash code option, at least for now.
P.S. I have curl functions working anyway, so I’m happy enough… Quick Pay Checkout works with Sandbox Credentials… But Not Production Credentials - Questions - Square Developer Forums