Arle's damage is already high without reaction, so yes you don't really need Yelan. Even if you want to use vape, you can just use Xingqiu. Use Kazuha and Bennet also for damage. And yes, PJWS is arguably Arle's 2nd best weapon after her sign since she wants to be on-field.
Xingque and Yelan can be used with Arrlechino. You don't need both. In floor 12 i tested them both and they differ by a few seconds. On avg Lil 5 secs with Yelan being faster of course. Just remember Xingque provides interruption and damage reduction tho
