To be ( slightly ) fair they are stressed beyond imagination but having issues with a new one is no good. Ground ls for rejection actually! I have just done this with a brand new 911.
True limp mode is about 2000 and runs on one cylinder only on the textron 750/850 . I have looked before for a definition of its limp modes and what triggers them without success. Overheating causes the 2000 rpm / 1 cylinder one I know for a fact but i don't know if there are other modes.
You say " drops back " so it runs normally to 7500 and then slows to 5000 rpm ?
If that is not correct please clarify.
5000 is the approx limit it will run if the turbo is stuck. If it is stuck it will be with salt and salt means a corroded manifold.
The fuel filter is not pressurise but they...
I did get Gallagher to quote following a recommendation from jfm. They quoted a haven Knox Johnson policy which was some £700 more than gjw which shows if is horses for courses - but I do wonder why the premium profiles can be so different for similar leisure users with decent boat time and no...
No boat will be perfect and age takes its toll.
The lift and survey would typically end in a price discussion if anything unexpected was found.
If the drive had anodes it is likely fine. But if not they are simple to replace and there will be a discussion with the vendor
Depending on price paid none of what you listed seems an issue.
Stern drives need maintenance and replacement bellows. They can and do go wrong and the bill can be significant.