Checking the ESOUI source code GetCollectibleFromLInk only works for linkTypes == LINK_TYPE_COLLECTIBLE
You can get the linkType by using
Code:
local linkType = GetLinkType(itemLink)
You can find this by searching for e.g. LayoutCollectibleFromLink (which is used in tooltips).
I'm not sure what you try to add to which tooltips and I never workd with the outfitd do far so I'm afraid I cannot furthr help you there atm.
But I guess those outfit link functions etc. only work at the collections -> outfit or at the outfit station item tooltips, and not for any normal items in your inventory/bank/etc.