Well now, that is a shame. But if the coach does not have some of your 'Must Have's', that are not easily added - then that means the coach is not right for you...
The other items, such as age of tires, are part of the bargaining dance. And no matter how nice a seller maybe, no reason to not treat this as business which should include a reasonable price point to cover outstanding repairs and maintenance items.
And a Buyer always has the right to ask for lower sales point, as does a Seller also has the right to not wish to agree
Best of luck to you on your ongoing search,
(And even with things maybe needing to be accomplished on this specific Manga, it sure was a gem of a coach and era of superior quality (Not just for CC, but for all manufactures...) At the right purchase point, this should be a fine coach for someone in the future. (Of course, that was without you going into great detail on what you inspection found...)