The Yeti has a 1.5 HT so a -2 head Angle is possible with a 1 1/8th steerer. Not sure how much you’d have to shorten the shock to get it from 180-140 rear travel, but it might be possible for someone like TFT to reduce the stroke without shortening the i2i. It might be worth keeping the forks at 160 as dropping to 140 is a fairly large difference, especially if you slacken it out as well. Might be worth double checking how slack the seat tube is before you add offset bushings, but then again they only cost £20 for a pair.
If the seat tube is slack you could just slide the saddle forward on the rails, I did and it made a world of difference after I fitted the offset bushings.
I think the BB was fairly high by modern standards so you might get away with it.
Ps – Jeron sorted me some offset bushings for my Alpine 160 and I love them (they did creak for the first 3 rides, but since then they’ve been super smooth). Also his customer service is brilliant. Thanks Jeron.
Tom KP