My thought is to remove the oil pan, too, and then start cleaning everything with a handheld steam cleaner, see what that frees up, and then it can drain out the bottom of the engine. I would start from the top (camshaft/valves area) and work my way down the front of the engine. Is this a good or bad idea?
Also, in a slap-your-forehead-moment, since I had to take the crankshaft pulley off I might as well order and replace the front crankshaft seal while I'm here. For the oil pan, it looks like that just uses a gasket sealer...there's no specific gasket, correct?
I have seen a lot worse than your pics, all depends on how often the oil got changed and with what oil.
Clean the oil pan, timing cover and valve cover and all unbolt pieces as good as you can.
I would NOT steam the block, you will knock loose many small chunks that you will never get out.
They will get down in the bearings and oil passages.
GM shows silicone for the oil pan gasket, some aftermarket gasket sets like Fel-Pro might have a real gasket.
A 2.5 mm bead is recommended, torque to 18 ft. lbs in sequence, use your judgement and watch the sealer push out evenly.
Crank seal change is a must, you should get one in your timing cover set.
When assembling, timing cover first and oil pan second.