I'm not understanding your question. What are you considering or calling a "Subscription check"?
I don't know what older Big Red plan you're on but almost all of the new plans have Hot Spot. The difference is how much data do you need for the Hot Spot. All of the data plans are unlimited unless you step down to a Pay As You Go, which are different initials than what you used, so I really don't know GUDP is?
As for Hot Spot on the new plans they work for Verizon Branded devices and Unlocked devices, even formally other carrier branded devices provided they are carrier unlocked.
On a side note Verizon could help you with this and provide answers for specific devices, just in case you're planning to get something outside of the mainstream.