Same motor mount.

Chain depends on clutch. Some use 219 some use 35. You could use the same no problem, just decide which one.

I haven’t tried to line up the WF and the LO206 regarding the sprocket hub, but it is not that difficult to slide it over on the axle, if needed. Depends on the motor mount and location of engine as well.

Throttle cable is the same setup, fuel depends on the rules.

I don’t really see any difference from putting the LO206 and WF on the same chassis.

Isn’t the LO206 fundamentally the same engine (block) as the WF?  As I understand it, it’s mostly the ruleset (and a few parts, notably the Ignition) that makes the WF faster.

I would imagine that you could swap them out with virtually no changes, provided you had the same motor mount & clutches.  FWIW, the LO206 is by far the easiest engine to remove that i’ve ever had.