Welcome to sailboat ownership and the SBO forums. You have chosen wisely the site to post your questions on. It is always good to welcome a new member, and I hope you have a long and enjoyable time on both your boat, when you make the decision to buy, and here with us.
I am not very familiar with the buying process of sailboats. My few purchases have been small and quick, but as an experienced used equipment buyer, and browser of the boating classifieds, I would say 15 months is a long time for a used boat to remain on the market. Your seller is probably motivated.
The mainsail will be expensive to replace, the bottom paint is probably something you should have done anyhow, unless it was just done, and the rest of the items sound fairly minor and the type of items you will have to replace someday anyhow.
It's good to start your new love affair with brand new fuel lines, reliable instruments, and fresh chaffing gear. You're likely to find more that needs attention as you get to know your new boat better, no matter what the survey says. Use the professionally appraised value as your starting point and land on either side of that, depending upon your gut, your bank account, and your conscience.
If you don't mind, please let us know a little more about your sailboat experiences and skill sets. Work you can do yourself may make something like replacing a leaky fuel line trivial, or even the roller-furling headsail. Having to hire a professional to not only replace the roller-furler, but also tune your standing rigging, will add boat bucks to the cost well beyond the part price.
Good luck and keep posting. We especially love pictures.
-Will