Q1: Yes

Q2: You seem to be worried about stopovers. On a OWE stopovers are only of significance in the continent of origin (i.e. Europe in your case) where you can only have two in total. In Asia or N America you can have as many as you want - the only constraint is max 4 segments in Asia and 6 in N America.

So man-lhr-bkk-sin-hkg-nrt-hkg-sfo is OK, but man-lhr-sin-dps-sin-hkg-nrt-hkg-sfo doesn't work for two reasons: 5 sectors in Asia, and no OW airline flies sin-dps that I know of.

sfo-hnl-lax-ord-lhr is fine and you could have 3 more domestic US segments if you wanted.

ord-lhr-dub-xlhr-man is OK provided that you go xlhr on the way out (only two stopovers allowed in Europe).