Can I play "Acerola" to return a damaged Pokemon and all cards attached to it to my hand when Lunatone's "Heal Block" ability is activated?
Yes, you can return the Pokemon and attached cards to your hand.
Source: Burning Shadows FAQ (2017-07-20), TPCi Rules Team (2017-08-03)
If I have a Solrock in play so that Lunatone's "Heal Block" ability is activated, does it apply to all Pokemon in play or just the two active Pokemon?
It applies to all Pokemon in play.
Source: Burning Shadows FAQ (2017-07-20), TPCi Rules Team (2017-08-03)