Have him adjust the trigger. That's it.
Installing a SAKO extractor will cost you about $150. There is a reason why Remington has three rings of steel. The first ring, the bolt head itself, is designed upon case failure to expand and seal the breech. Milling out the bolt to accept a SAKO type extractor defeats that safety design. Keep that in mind.
Bolt handles can break off, but this rarely happens. If you're that worried, you can have it TIG welded or get a one piece PTG one fitted.
As for safety, I think it's a good idea. I have a PTG swing type safety, but have been too lazy to install it.
Keep in mind the more you spend, the happier your gunsmith will be. It's ducats for him. Consider if you can use the money toward other things like paying off bills.