To answer your questions:
1. Yes. I think the tendency to go pink will be down to the original paint manufacturer which I think changed at some point. Some more knowledgable than I will no doubt clarify. I would go back to view the car again with some T-cut and try a sample area.
2. I used the full Maguiares treatment on mine and it worked wonders. It involves washing, claying, compounding, etc etc. Took all day but what a difference. Look at some youtube clips of Maguiars.
3. Will depend on outcome of 1
Bear in mind the following:
1. Its likely to need a new cambelt/water pump as it needs a new cambelt every 5 years regardless of mileage and you may as well do the water pump while you are there. Knock off £750 if it hasn't been done.
2. Bad rust on the rear wishbones. Take a magnet as there have been instances of people covering the holes with fibreglass and then painting it all up. Very expensive to do properly.
3. Rust on the front wishbones. Same as 2. Look at
http://www.sjsportscars.co.uk for prices of parts and you'll see what I mean.
4. Rust on the chassis especially in the suspension turrets which is not easy to see. The chassis is not galvanised as some think, its actually powder coated and the coating is now coming off most cars in awkward places. Everything can be sorted but bear in mind you'll unearth a pile of other work and the car will be off the road when you really want to just drive it.
5. I wouldn't buy a car now unless I could get it up on a ramp and have a real close look under it. They all look good from the outside.
6. The tyres have probably got flat spots on them and need replacing and the brakes are probably seized.
For me 1 and 6 are worth negotiating the price down if everything else is OK. The rest would be deal breakers unless I could get it at an absolute bargain price. Get the owner to put it through an MOT (even if it has one in date) and see what comes up. If you are there when its being done you may be able to get a good look round it and underneath it.
Personally, unless the paint is peeling, I wouldn't really worry about it. Its the hidden thats a greater concern. Hope that doesn't put you off.
Andy