[@Duthguy]

If you want to try and block the next attack onto Lilt, you got two options:

You could try and serve as a sort of half cover for her to increase her AC by 2, as well as grant the enemy disadvantage on their attack towards her. May or may not be worth against a cyclops considering their already immense attack bonus and Lilt’s Relatively low AC.

As your readied action you could make yourself the target, however the cyclops will have advantage on the attack since you’re purposely trying to get struck by him on Lily’s behalf.

Which ever two you feel like using really.

[@floodtalon]

You’re attack of opportunity is a reaction done outside of your turn, so yes you can, though your attack of opportunity occurs first before the spell casting. Cyclops moves away > Attack of Opprotunity > Ano’s Turn.