That's why I expect for the LRD/SRD they'll put a pair of smaller, as yet unseen motors. Matching the rear with the front.Unless they downsize the rear motor in the Model 3LRD, adding a front motor, even a 200hp/250lb (gross) one will most likely turn it into a 3.x second to 60mph variant at 4100lb capable of running high to mid 11 second ETs at 112-116 mph. This is assuming the battery won't fade for 12 seconds or they don't deliberately detune it.
Then keep the large in the rear for the P with the small one in the front, along with those other refinements you mention to account for all the HP it can get to the tires. LR only of course, if not a slightly beefed up version of the LR battery pack, to avoid hitting their head on the battery pack C/thermal limits.