Next level in NLL area provocation is the sustained attack on one of these islands, and attempt to occupy it. It will be a mini-war. That is in the pipeline, too. It could happen down the road, if situation develops in their favor.
Probably a full frontal assualt is next of Baekryongdo Island, first, considering, a) it is isolated...this is how the DPRK gang up and “jump” the enemy, like M-13 gangs, when he is isloated and with little nearby support, b)could take taken after intensive bombardment, and then stormed by special North Korean landing troops. I think South Korea should stay on FULL ALERT and raise security level to the highest possible. I also believe US should consider evacking civilians from Seoul.