I feel similarly: I think I prefer the look of
Petula to the sound.
A
Petula combo I thought of a while back was
Petula Odetta, combining the interesting names of two singers from the same era, but I think
Petula Odette sounds nicer.
Petula Sally Olwen is such a great combo, on the original
Petula, it's hard to beat that!
Of your combos,
Petula Enid struck me as really lovely; and
Petula Mirai made me smile (I do love Mirai).