I think both her Parasol customs are bad. Light Parasol can be opened/closed 7 times if you are fast enough. This covers huge vertical and horizontal distance, but it is much too slow and easily punished. Her standard Up-B is really good anyway.
I think Flying Bomber is the best because of the combo potential. It allows Peach to finish a D-air combo and retain her second jump+float. Also, with Flying Bomber you are free to move whenever you touch the stage, meaning this can be spaced to recover to the stage or a platform (e.g. Battlefield) with no lag.
Sleepy Toad is good, but I personally rarely land grounded counters, so I'd rather use the original.
Good points can be argued for all 3 turnip types. Light Turnips are good for approaches and zoning, Heavy Turnips are good for damage and combos, and Default Turnips are in the middle of both extremes.