Hello out there,
I just saw a bunch of videos concerning the new features of the newest Lightroom update...now I wonder if you can use the feature of changing the hue of a masked area within the editing of the keyframes one created in LRT...I’m just being curious...

Those new hue options should be in 5.4 already, did you try? If not they will be in the next upgrade.

Not yet...but the more I think about it the less situations I can imagine to use this feature in a useful way...

Personally, I don't even see a need for that Hue slider in regular Photography... ;-)