Chairman Kaga said:
No. A card has to actually be released before it can get an errata.
I'm not so sure. Pokémon Organised Play are dedicated to ensuring play is fair and cards are given accurate errata if necessary. If POP became aware that a card to be released was being played incorrectly at pre-releases, I'm confident they would make it known. Pre-releases are still tournaments and should be played as intended, and players should have the right to accurately prepare for a tournament regardless of whether they will be using their own cards.
As for energy payments, they can actually be paid in different ways. Whenever you are required to discard a set number of energy cards such as 2 or 3, you just move that number of physical cards to the discard pile. Count the physical cards as you pick them up from the pokémon until you have discarded enough. Then stop! you can't discard any more.
If it just mentions "energy", the process is very different. You can actually discard more energies than is needed if you choose the cards in the right order. For each card you discard, count the number of energies it was providing. That's one for basics, three for an activated scramble energy etc. When you get up to the number it's asking for, stop! you can't discard any more.
For your Latios, suppose you had three basic energy cards attached and a holon's castform. You could discard the holon's castform and then a basic energy. You would then have to stop, because you reached three. If you discarded two basics first, you could then choose the holon's castform. Even though that goes over the three it's asking for, it's OK because you didn't reach it until then. You could discard just the three basic energy cards, but not all four energy cards.
In your post, your understanding is right. Even though the special energies you mentioned cannot be attached to basic pokémon, can you see from my example that you can still be in a similar position with holon's castform?
Hope that was helpful.