Which decks are you going to slot them in, and which legends are inspiring you to build new decks
A loose guide for grading whitening would be something like: No whitening - GM 10 1 to 2 spots of whitening - 9 Mint 3 spots of whitening - 8 Mint/Near Mint 4 or 5 spots of whitening - 7 Near Mint All 4 sides have whitening - 6 or below Color boarder cards have a hard time gem minting compared to cards with white/grey (think modern) borders since things like silvering/whitening are much less noticeable
Battle flairs are an impact cosmetic, sparks or clouds of dust that fly off the card as its played in a battle, for instance
Rapid Strike Urshifu VMAX Rapid Strike Urshifu VMAX (Battle Styles) certainly differs from its Single Strike version by taking inspiration from Raichu & Alolan Raichu-GX (Unified Minds), Pikachu & Zekrom-GX (Team Up), and Golisopod-GX (Burning Shadows)
I think there is some kind of deal when you spend enough money and keep your receipts
All Family Size cereals, however, contain a chance to get a special 14th card, Galarian Ponyta