I can't claim to offer any particular insight here, but a more pro-US bent to Cuban foreign policy post-Castro could signal a change in a lot of other policies, including towards the Polisario. Currently the pro-Morocco lobby in the US Congress essentially consists of anti-Castro Republicans and pro-Israel Democrats. Post-Castro, would the former really care anymore about Morocco's forgotten conflict?
Also, there might be other Castro-Middle East links I'm forgetting about. Can anyone think of any?