Can I remove this paneling from behind the wall?
No need to cut the panel behind the dry wall.  You have already made the decision to cut the drywall to gain access behind the drywell.  Just cut a little more below your current cut .  Insert drill and drill up through the blocking.  You may have to use a 6 or 12” extension with the bit to drill through.  Extensions are only a couple of bucks.
There are flexible drill bit that can reach 6' or more.  If there are only two fire blocks these would work.  Use regular drill and extension for the first block.  then use flex drill bit to reach the second block.  The flex extension can pull the wire or a string to pull the cable back down.  These are used a lot to pull security wire through out a house.  Cheap one from HF cost about $8,  Good ones about $25-30 dollars.
If you have difficulty in fishing the wire through the blocks after the holes are drilled.  just cut a 3&quot; circle above the block in the panel and fish it through by hand.