Cape Dory 30
I am sorry to hear that you ran into problems with the survey. I was delighted to read your excitement about the deal progressing. I know how heart breaking it can be to think you have the ''perfect boat'' only to find it rift with problems.
As to the problems, I can''t recall if the Cape Dory 30 has a bolt on or an encapsulated keel. If this is an encapsulated keel, then I would run and not walk the other direction, because once the encapsulation had delaminated from the ballast, and the encapsulation envelope has been breeched, there is no practical repair that will return this boat to a "like new" condition because there is no way to get the moisture out of the keel cavity and re-adhere the ballast to the shell. (I am not sure that the CD30 had lead ballast as I seem to recall that some of the CD''s had iron ballast. If the CD30 has encapsulated iron ballast, that makes the situation far worse and harder to repair.)
If this is simply a bolt-on keel the repairs are somewhat easier, although there are some potentially negative implications to those as well. It is actually pretty easy to unbolt a keel and rebed it properly. If the CD30 does have a lead keel, then the weeping would suggest corrosion of the keel bolts and a keel bolt replacement is a very big job.
When you combine the keel issues with the deck core issues, this is a major project boat. You have every reason to request your deposit back because this by any reasonable definition this is a boat that failed its survey with concealed conditions that you could not have known about prior to making your offer. The kinds of problems that this boat has are severe enough that $10-12K will not result in a seamless repair and so simply getting a $10-12K discount would not make you whole. This is clearly a boat that has had a hard life and frankly it makes no sense for you to take on the problems of the current owner. I strongly suggest that you demand your deposit back and look for a decent boat.