Re: 8:01pm.
Upon the explosion, Ysmir will be startled but that moment will be fleeting and he will instantly go into action mode. He will use his bow and arrow to snipe out as many Gremlins as he can and if they get too close, he will use his sword to put them down. To give his surrounding allies a boost, he may use "Battle Fury" which basically gives them a nice speed boost with their weapons.
Christian will probably see Winry struggling with Gremlins and go into fighter mode and help her by subduing the creatures with his fire magic so she can take them down quicker. He'll also take a fair few of them down himself just by sending fireballs after them.
Myron will be using whatever spells he can to deal with the Gremlins. Might use Wingardium Leviosa on small groups of them to drop into the bonfire because that's an effective way to get rid of them.