Hi everyone:
It has been my dream to own a Steinway B since I was young, but due to financial constraint I can't afford to get a new one. Today I came across a used Steinway B for sale, but like all used pianos, it has some problems. I do not have the technical knowledge to decide whether it's a good choice, and any help would be appreciated

The piano was built in the year 2001. It's very lightly played (so lightly played that I could hardly see the string marks on the hammer felts). However, the person who plays the piano is a beginner kid, so the action in the middle is a bit uneven. There are bigger gaps between keys in the middle section (1 octave above and below middle C to be precise). I have a sense that the player has been moving his wrists sideway/wiggling his wrists quite a bit when he plays. The rest of the keyboard is fine though. Is this a permanent problem that can't be fixed as if it's just aged unevenly? or do you think a professional technician can solve this problem? What kind of services will be needed?
Also, the owner removed one spring from the damper pedal to make it easier for his child to play the piano. He still has the spring. He said it should be very easy to add back the spring to the pedal, and his removing it before shouldn't have hurt the piano at all. Is it true? I can tell that with one spring being taken away, the gradations of the damper pedal is lost.
The owner has a pet at home. There's quite a bit dust/fur inside the piano (which I totally understand. After all it has been 12 years). Is it possible to ask a technician to clean the piano completely?
Finally, the action of the Steinway B feels rather light for me (lighter than other Steinways I have tried). The owner said that the key-weight of his piano should be around 50 grams, but somehow I remember people telling me that a Steinway grand has a key-weight of about 65 grams. Is that easily adjustable?
To be honest I love the sound of the piano. My biggest concern is that the middle section is a bit overused while the other keys are basically untouched. I hope you guys will be able to offer me some suggestions/comments.
Thanks~