You can play Mallow & Lana as long as you have a Benched Pokemon. But if your Active Pokemon is not damaged, you cannot discard 2 cards from your hand.
Source: Cosmic Eclipse FAQ (2019-10-18), TPCi Rules Team (2019-10-31)

Relevant cards

Note: All applicable cards may not be listed below.
SM12_198
SM12_198
SM12_231
SM12_231