You've found the two FAQs that are relevant. The FAQs have the same authority as the standard, they expand and clarify it but are written, reviewed and approved by the working group that also writes the DSS. There are two issues.

1. Does a correctly truncated PAN require the protection of all the DSS requirements? The answer is NO - FAQ 1117. BUT as @eckes correctly points out, you need to make sure the environment that contains just the truncated PANs is not "connected to" your CDE.

2. Can you keep an 8 digit BIN when you truncate a 16-digit PAN? The answer is YES - FAQ 1091. You can retain "first 6, any other 4" -- so that can be NNNN NNNN **** **NN

You've found the two FAQs that are relevant. The FAQs have the same authority as the standard, they expand and clarify it but are written, reviewed and approved by the working group that also writes the DSS. There are two issues.

1. Does a correctly truncated PAN require the protection of all the DSS requirements? The answer is NO - FAQ 1117. BUT as @eckes correctly points out, you need to make sure the environment that contains just the truncated PANs is not "connected to" your CDE.

2. Can you keep an 8 digit BIN when you truncate a 16-digit PAN? The answer is YES - FAQ 1091. You can retain "first 6, any other 4" -- so that can be NNNN NNNN **** **NN

3. Can you keep two truncated PANs: a first 8 last 2 and a first 6 last 4 in the same environment? The answer is NO unless you want that environment to be in scope of all PCI DSS requirements because basically you're storing the first 8 last 4, which doesn’t meet the truncation requirement.