As you say, the original can't possibly work - there's probably not enough current available from the parallel port to blow the LED?, but it won't do the port any good!. As you also say, the second opto-coupler prevents MCLR from rising above 2V or so.
The two resistors you added might make it workable, and I would also add a couple of capacitors round the voltage regulator. Bear in mind, assuming it does work?, it will require a fairly accurate and stable supply voltage (as there's no MCLR regulation incorporated).