This /t/WaniKani-to-Anki-Exporter-httpwanikanitoankicom/5055/1
will create an Anki deck of all your learned WK items.
As far as using kanjidamage mnemonics, there is probably no easy way to bring them into WK. You CAN add your own notes to any item in WK tho, so you could always do it manually.
There is also this /t/Userscript-Community-Mnemonics-v0978/7367/1
that adds community mnemonics to WK items, those might help you.