Yes.
Depends entirely if you are running automated MQL sync and/or syncing your programs to SFDC.
If you are NOT auto syncing programs, then you should be ok. Just make sure your MQL flow excludes this static list you upload.
If you ARE auto syncing programs, then you should add a field in SFDC that says "Do not sync"=TRUE. Add this to your MQL flow to prevent syncs. Then tell SFDC to NOT accept any leads with Do Not Sync=TRUE. The SFDC insert will FAIL.