Ho-Oh EX's Ability

[Vulpix Yolk]

Ho-Oh-EX – Fire – HP160
Basic Pokemon

Ability: Phoenix
This ability can be used 1 time during your turn if this card is in your discard pile. Flip 1 coin. If heads, attach 3 different Basic Energy cards to this card and play it onto your Bench.

[C][C][C] Rainbow Burn: 20+ damage. Does 20 more damage for each different type of Basic Energy attached to this Pokemon.

When Pokemon-EX has been Knocked Out, your opponent takes 2 Prize cards.

Weakness: Water (x2)
Resistance: Fighting (-20)
Retreat: 2

My question is, can you attach less than three basic energy cards from your hand to Ho-Oh after using Phoenix? Can you use the ability if you don't have three different types of energy to attach exactly? Would I be allowed to attach a single Water Energy if I wanted to? Thanks in advance.

[PokePop]

That doesn't read like official text.
I can't answer this question.