#1-DO NOT use that Melling oil pump. The gearset in the pump is not of the proper hardness,and will manage to eat itself in 15-20K miles-ruining the engine. I've been there once already. The OEM pumps are the best to have on a modular, unless you want to get one of the very few quality "billet" gearsets to use in the OEM pump body.
#2-you have some issues there,and IMO-you've got damage to the cylinder head cam bores if you have that much metallic trash in the pan. The cams are at the end of the lubrication circuit, and are the first thing damaged when oil pressure drops.
JL