Re: Will linseed based blue tones turn all to green?
Short answer - no.
I was surprised to find in my own testing, that whereas whites bound in linseed oil will yellow after dark aging, blues and blue tints generally do not.
EXCEPT for PB15:4 which is often thinned out and marketed as manganese hue. I have an alkyd version of this paint and it does turn quite green even when not dark aged. That said, maybe the non-alkyd, or better pigmented version, or version bound in another oil would fare better.
Also, as others have pointed out - L&B uses either safflower or poppy oil (I think they use linseed for darks/earths though?). Either way, no need to worry.