I'd just use the Japanese errata on Slowking, and remind everybody that Sneasel has 60 HP. But I'm weird...
I would like that idea.
If I were a judge, I would probably brush up on those cards that are used often and have a lot of text:
Gold Berry (Neo Genesis)
Chaos Gym (Gym Challenge)
Brock's Ninetails (Gym Challenge)
Ditto (Fossil)
If you use the old metal rulings, be sure to brush up on Erika's Dratini and Neo Metal Energy.
Confusion did 20 damage to self and applied weakness and resistance. Check ruling with Dark Primeape.
Mulligan of draw 2 cards.
Retreat once after the modifications?
Retreat on Confusion? It used to be you had to flip to retreat and pay the cost. If heads everything worked as normal, if tails you did not get to retreat. But since you could retreat as many times as you wanted , could you retreat again and pay the cost again for confusion?
What's that ruling with Chaos Gym and Slowking again?
What about the "optional" mulligan with Mysterious Fossil?
Does a Poisoned pokemon with a Pokemon Power get shut down?
Char counters what are those?
As far as I am aware archetypes might be:
Giovanni's Machamp
Blaine's Magmar/Entei/Cleffa
Raindance
Damage Swap
Haymaker
Sneasel / Pichu
Do the Wave
Clefable/Muk
Muk/Dark Muk
Moltres (Fossil)/Dark Vileplume / Entei
Rocket's Zapdos
Babyporter
Dark Charizard w/ Dark Dragonair w/ Entei???
Feraligatr / Parasect
Entei / Magcargo
Slowking / Sneasel
Sabrina's Alakazam
Lt.Surge Deck w/ Rocket's Zapdos
I did not play competitively at this point, but those would be what I think are some of the archetypes at the time.