Hey Kyle sorry for the delay
Im gonna replace the head insert for peace of mind as its only like $40, Im also getting prices for a new cylinder as i dont really want to use the one we have. Also the guy whos doing the engine work has looked it over and said he wouldn't want to use it either! And as you've also said about the sleeve showing through!
Stained impeller? Could that be a sign the previous owner used water? As it sure looked like water that came out

There was only one blocked water passage! Its all coming apart soon so needs a good flush out ect,
Pics below


The rust colored stains im not sure on? Only thing i can think of is the old owner never used coolant as said it looked like water! Yeah i agree about the porting just maybe gone through to much material!
Thanks for the advice guys