Advice on a 990

Last thread I'll open; promise  :

I'm lining up to buy a 2009 990 Adv with 40,000km on it for R85k. It's got a tall screen, aftermarket pipes of some sort (look like Leo Vince), tank bag, crash bars and heated grips. Seems like a good deal.
It's in George so I'll need someone to go and take a look at it for me, but I'll get to that. Then I get to ride it back to Jhb  :ricky:

I have read this thread which was helpful. There are a few items on there that I'll be looking out for but there are others I'm not sure of:

• I know about the clutch slave cylinder issue but how do I sort that out? Is it a big job? Who does the fix and how much does it cost?
  
• Canisterectomy? I've tried reading up on this but I'm not grasping how important it is or how to get it done.
  
• The bike hasn't been used much over the last few months. Is the battery the only concern or is there something else I should be checking?
  
• Considering it's been at the coast all its life, are there any rust-prone bits I should be checking?
  
• Lastly, the seller says he's going to take it to his local KTM-friendly bike shop for a once over before he sells it. Considering I'm going to jump on it and ride 1500km or so back home, is there anything specific I can ask them to check or do?

Thanks