In the same condition, a G11 beats a K11 because of the much, much longer sight radius. Also beats most other rifles with open sights. Clearly beats any rifle with Mauser-style V-sights. The bolt is easy to dismantle and reassemble once you know the trick. You should be able to find an online tutorial, or get "Military Rifle Disassembly and Reassembly". The tutorial for the
K31 bolt at the head of the forum should help you.
The price for the rifle would be high over here - no WWII mystique. I cannot comment on your local market.
Go for the ammo - it seems like a fair price, it is not going to get any cheaper, and you need to be an expert reloader to even equal the GP11 ammo, let alone improve on it. The most accurate surplus ammo I ever found. You will probably find that the G11 with GP11 ammo outperforms most of the other rifles on your list, all of which I have either tried out or own myself.