I agree that there is very little chance of RNS or CFR being served from LON in the foreseeable future.
HOP will be suffering from the fact that French government aid to AF was given on the proviso that 'unnecessary' domestic routes be dropped so they may in due course look to establish more short haul international routes. When normal times return; perhaps in Autumn 2021(?) no doubt both CFR and RNS will be looking to re-establish their LON links but it must be doubtful that SEN will benefit next time around.