"Low priority" is inevitable when you have hitboxes as precise as WFT's...
In reality there is no such thing as "low" and "high" priority. Priority is simply determined by damage output and a single flag. If two (ground) moves clash, then one of the attacks has to deal at least 9% more in order to outprioritise the other attack. Aerials nearly always beat out ground moves. Attacks can have a "transcendent" flag that gives them transcendent priority, allowing them to go through any attacks regardless of damage (see: ALL BUT TWO of Metaknight's standard attacks in Brawl).
However, moves with smaller hitboxes tend to seem like they have lower priority because without good spacing, you're going to get hit by the other hitbox before priority stuff happens. That's the main issue with WFT, so what you need to make the most out of her attacks is really REALLY good spacing.