Need advice on issues before purchasing a boat

Hi all!

I wanted to get your advice or suggestions about a Yacht I'm pretty close to closing on.

It's a 2005 Cruisers Yachts 540 Express. I've done a sea trial and just did the marine survey and inspection. Here is a list of the things that don't operate.
Exterior running lights as well as some interior lights don't turn on.
Horn doesn't work.
HVAC below deck works great, however up top, it doesn't work.
Stern thruster is not working. I inspected the props on haul out and they don't spin freely. It's completely seized.
During the sea trial, just several days ago, the engines ran amazing. They both ran at about 170⁰. During the survey sea trial yesterday, the starboard motor got up to around 200⁰ after running full throttle for several minutes. Once we backed off and slowed down, the temp dropped down fairly quickly.

Please share your thoughts. Are these issues a serious concern? What do you think are possible causes for these issues? What should I expect these repairs to cost?

I appreciate any input.

Thanks!

Thank you all for the replies and info.
The engines are Volvo Penta D12 715. They both have just under 1100 hours each. I'm hoping it's something as simple as salt buildup on the heat exchange. But wanted your opinions.

The oil samples all came back with zero issues. Everything was marked green.

Regarding the AC. Below deck, it works perfectly. The control panel on the flybridge doesn't turn on or respond. No breakers trip.

The outside navigation lights as well as the lights inside on the flybridge don't work, nor does the horn. My thought is that it could be an issue with the main control board panel as all the switches are built into a one piece soft panel where each switch is not accessible. From that panel, there are 4 or 5 wires that go down to a main control unit. As the boat is not yet mine, I haven't been able to dig further into this.

Most likely, I will ask for a price adjustment to cover repair costs. I just want to get an idea as to what would be a fair number.

I've worked on my own cars for many years including electrical work. I'm new to working on boats.

I wouldn't go that far. The vast majority of things do work on the boat and it was very well maintained. It's incredibly clean. The hull is perfect and was surprisingly very clean with zero buildup. The only mechanical issues are the stern thruster and the starboard engine running hotter than it should. It never got to the point of being considered overheating.

I've yet to be on any boat where absolutely everything works. It seems like either the horn, speedometer, or fuel gauges don't work on every boat I've been on.