With Gandalf on the field, Lagrella enters the battlefield and takes two permanents from each player because she is a legendary creature and she is triggering a permanent (herself).
However, when she leaves the battlefield and the other creatures return, her suspended ability puts two +1/+1 counters on those creatures if they enter under your own control (i.e. if you took your own creatures and now they are returning to the field).
If Gandalf is still on the field, would those creatures get four +1/+1 counters instead? Would those creatures only get four counters if they themselves are legendary? Am I completely off the mark and those creatures only ever get two counters regardless of Gandalf?
Thanks for the help!
Lagrella's delayed triggered ability that puts counters on creatures triggers off of the exiled card entering the battlefield, so the exiled card has to be legendary for it to get the additional trigger. It couldn't use Lagrella leaving the battlefield as the trigger because the card isn't on the battlefield yet to have the counters placed on it.