Inspirational Antelope is not legal in any format.
Rulings
2019-11-12
An ability word appears in italics before an ability and has no inherent rules meaning.
2019-11-12
If an object becomes a copy of an object with a word blank, the value in that blank is copied.
2019-11-12
If you choose a keyword that usually takes a modifier, such as costs for abilities like cycling or numbers for abilities like crew, don't include any such modifiers. For example, if you write "cycling," all spells you cast with a cycling ability cost {1} less, no matter what their cycling costs are.
2019-11-12
Once you've written a word for a word-blank legacy ability, you can't change it, even between games. It remains part of that physical card
2019-11-12
To choose a keyword ability, you may select any keyword ability (such as flying, hexproof, or legacy) but not a keyword action (such as destroy, populate, or scry).