The noise could be a variety of things including the belt tensioner pulley, power steering pump, alternator, A/C compressor... You can buy a mechanics stethoscope to try and identify which component it's coming from, or bring it back to the mechanic who did the WP / TB for diagnosis. Same applies to the oil light. It could be a bad oil sensor or the pump... I haven't heard of many LS's with that many miles on them so its hard to say exactly.
Can you take a pic of the odometer and post it up on this site? That's a lot of miles!