We'll be in Bunaken - Lembeh starting end of mai.
I have some information, no problem in this region... only the closed airport
But it's only temporary (I hope)
Don't forget that the Ruang is more than 100 km from Lembeh..
If the vulcan generate a tsunami it will be only dangerous for the island place at a short distance Lembeh is also protected from the north part of the "North Sulawesi"
I saw a simulation. 45 min for the SMALL waves to arrive at Lembeh