Trainers » Misty & Lorelei
Can I use the second part of Misty & Lorelei to discard 5 cards if I have not already used my GX attack for the game?
No, you cannot. If you haven't used your GX attack yet, you can't discard 5 cards from your hand.
Source: Cosmic Eclipse FAQ (2019-10-18), TPCi Rules Team (2019-10-31)
Trainers » Misty & Lorelei
When I play Misty & Lorelei, can I discard one or more of the 3 {W} energy I searched for as part of the 5 cards discarded to get the re-use of my GX attack on this turn?
No. You have to discard 5 cards "when you play this card". That is before you search for the {W} energy cards.
Source: Cosmic Eclipse FAQ (2019-10-18), TPCi Rules Team (2019-10-31)
Trainers » Misty & Lorelei
You can play Misty & Lorelei for the base effect as long as there's at least 1 card in your deck. You can always play it by discarding 5 cards from your hand.
Source: Cosmic Eclipse FAQ (2019-10-18), TPCi Rules Team (2019-10-31)