Umbreons status as the most popular of all Eeveelutions inherently raises the value of this card
Whether the release notes will account for that case or not, you could address the head judge and ask them to allow cards outside of the sideboard as well , as they have the authority to rule one way or another if in doubt
Rogues A common theme across a few of these "party" cards is that they often cost less for each creature in your party
General pwcc , charizard , question 70 12905 November 20, 2023 Thick Vs Thin Stamp General question 36 24875 March 28, 2020 Grey Stamp Theory General general-board 15 10172 June 29, 2017 Grey prints General general-board 10 516 August 2, 2017 Price Check, Back Stamp Misprints /1st Ed
In context of the card, it appears to represent "disassembling" a creature and giving its "pieces" to other creatures on the board until the end of the turn