They're really cheap cams. Resolution isn't all that good, color's a bit off, but they work.

Welding - I didn't think of that. The pins on those chains are probably pretty cheap metal anyways.

MCLR cap - usually, it's there to keep MCLR held off for a split second during power up. The built-in power up timer handles that for 72ms if enabled. And the cap will also help with keeping transient power flux's from tripping MCLR.

40mhz vs. 20mhz - If you've got anything 5-10mhz laying around, try enabling the internal 4XPLL. The board should run at 40mhz, especially since you aren't trying to interface with anything major like static ram or whatever...yet...