If you're going to edit the NFO file you need to use tags and not edit the genre. The genres will be reset if the NFO is replaced either by you or by some media manager (Sonarr). This is what you'll need to do if the content is in your library.
That said, this is how I handle "special" content (Halloween, Christmas, etc.) I have content outside of the library so as not to have to browse past this content during the year. Much of this is science and nature, food and travel, and documentaries - stuff my family doesn't want to see or deal with to get to the "normal" shows or movies.
I keep this stuff in a folder named "Other" and get to it with an entry in the "Favorites" folder ("/storage/.kodi/userdata/favourites.xml"). Because I don't want to see seasonal stuff throughout the year I keep Christmas, Halloween, and Thanksgiving content in hidden folders. Screenshot:
Then right before the holidays I edit the favourites.xml to include the hidden folder on the Favorites page in kodi. These are the three lines that get added to the favourites.xml file:
xml:
<favourite name="Halloween" thumb="/storage/nas/media/admin/graphics/Square Covers/logo-halloween.jpg">ActivateWindow(10025,"/storage/nas/media/Other/.Halloween/",return)</favourite>
<favourite name="Thanksgiving" thumb="/storage/nas/media/admin/graphics/Square Covers/logo-thanksgiving.jpg">ActivateWindow(10025,"/storage/nas/media/Other/.Thanksgiving/",return)</favourite>
<favourite name="Christmas" thumb="/storage/nas/media/admin/graphics/Square Covers/logo-christmas.jpg">ActivateWindow(10025,"/storage/nas/media/Other/.Christmas/",return)</favourite>
Here is what my current favourites.xml file looks like now in preparation of Thanksgiving:
xml:
<favourites>
<favourite name="Thanksgiving" thumb="/storage/nas/media/admin/graphics/Square Covers/logo-thanksgiving.jpg">ActivateWindow(10025,"/storage/nas/media/Other/.Thanksgiving/",return)</favourite>
<favourite name="Other" thumb="/storage/nas/media/admin/graphics/Square Covers/other1.png">ActivateWindow(10025,"/storage/nas/media/Other/",return)</favourite>
<favourite name="Other" thumb="/storage/nas/media/admin/graphics/Square Covers/other2.png">ActivateWindow(10025,"/storage/nas/temp/Other/",return)</favourite>
<favourite name="Music Videos" thumb="/storage/nas/media/admin/graphics/Square Covers/logo-mtv.png">PlayMedia("special://profile/playlists/video/Music Videos.m3u")</favourite>
<favourite name="WSHE Classic Rock" thumb="/storage/nas/media/admin/graphics/Square Covers/wshe.jpg">PlayMedia("/storage/nas/media/Joey/Streams/wshe.strm")</favourite>
<favourite name="Rebel 99 Rock" thumb="/storage/nas/media/Joey/Streams/Rebel 99 Rock.jpg">PlayMedia("/storage/nas/media/Joey/Streams/Rebel 99 Rock.strm")</favourite>
<favourite name="Netcasts" thumb="/storage/nas/media/admin/graphics/Square Covers/netcasts.png">ActivateWindow(10025,"/storage/nas/temp/Other/Netcasts/",return)</favourite>
<favourite name="Science and Nature" thumb="/storage/nas/media/Other/Science and Nature/folder.jpg">PlayMedia("special://profile/playlists/video/Science and Nature.m3u")</favourite>
<favourite name="Star Trek: Strange New Worlds" thumb="/storage/nas/media/Everyone/TV/Star Trek- Strange New Worlds/poster.jpg">ActivateWindow(10025,"videodb://tvshows/titles/355/",return)</favourite>
<favourite name="Star Trek: Voyager" thumb="/storage/nas/media/Everyone/TV/Star Trek Voyager/poster.jpg">ActivateWindow(10025,"videodb://tvshows/titles/51/",return)</favourite>
<favourite name="MasterChef Australia" thumb="/storage/nas/temp/TV/MasterChef Australia/poster.jpg">ActivateWindow(10025,"videodb://tvshows/titles/245/",return)</favourite>
</favourites>
I use a bash script via cron to automatically swap-out my favorites file at certain times of the year. But, you can just edit the file manually - I did this for years.
Hope this helps,
Joey