Honestly, I think Izana at 1 would be fine. Her S/T removal effect is balanced and she's still vulnerable to effects that don't target (Wall of Disruption, Drowning Mirror Force, etc). The main issue is her ability to attack two opponent's monsters, I think...
Natasha's one of the best Cyber Angels due to her OPT (Quick Effect) Ritual Monster protection from everything. Since DL only has 3 slots instead of 6, that makes it even stronger.
Not only that, but her and Benten are the easiest to bring out - and probably the two easiest rituals in the game to bring out (due to low levels, multiple dedicated ritual spells, and having support).