I think no, but just to check...

Does the Kaa'to Leeachos action count as the donor "spending" a focus? I.e. Say Kaa'to takes the focus from a Y wing or Jumpy with OcR4, can the Y wing or Jumpy gain a stress to get another focus token?

Cheers

No. Stealing a token from someone does not count as them spending it.

If they both have Mindlink this works. Steal it from a buddy, then Mindlink triggers when that ship is assigned a token, and Kaato gets one, too.

Too bad Garven Dreis can't take Overclocked. He could hand off a token and OC to regain it every time he spends one.