I am stalled on a build of Tamiya's 1/350th Prince of Wales from the Denmark Strait action & she carried the same colour scheme as the KGV. This was AP507B medium grey on the vertical surfaces & AP507C Dark Grey on the horizontal decks & turret tops. For my POW, I have used White Ensign Models Colourcoats enamels, who do the exact shades. Teak is a sticky subject, as its colour can vary dependant upon whether it has been holystoned of left for a while. White Ensign do a teak & it is quite light, so I am guessing that it is as just sanded, however, as it ages, it can go to an almost grey in colour...or so I have been told.
What might be a problem is the period that Tamiya have based their 1/700th KGV on. I know that their 1/350th KGV is late war & judging by the only photo that I can find online of a built 1/700th one, this is too.
At the time of the Bismarck action, the KGV would have carried a Walrus seaplane amidships. Later in the war, it was landed. The catapult area was used for boat stowage & the hangers were used for accomodation for the increased crew needed for the greater AA battery carried. The Tamiya 1/700th kit looks to have boats stowed amidships. Also, at the time of the Bismark action, both the POW & KGV had what is probably the most useless AA weapon ever fitted, the UP. It fired rockets that dispensed an aerial mine, that was suspended by a parachute & was supposed to float down in the path of the enemy aircraft, be snagged & explode.
One was fitted on top of the B Turret, two on the rear Turret & one or two at the stern. Shortly after the Bismarck action, these were replaced with 40mm Pom Pom mounts. (Interestingly, Tamiya's 1/350th Prince of Wales box shows a picture of her as she was in May 1941 with them fitted, but they aren't included in the kit. White Ensign Models do them in resin in the scale & I have used them for my POW build) The later war KGV also carried 20mm Oerlikon mounts, which were pretty much absent in May 1941 as well as increased radar.
A great source of reference on the class is V E Tarrants book on Kinge George V Class Battleships. Sadly, my copy seems to have gone AWOL, otherwise I might be able to do a bit more than work from memory.
I can't help you with the boat colours etc though. Sorry.
Regards.
David.