Just soloed this as a 50MNK/25DRK.
Of the three mobs for LB1, I think this might have been the tougest for me. That could just be due to the difficulty of getting through the Banishing Gate.
Thanks to the other posters, I found the correct place to camp these guys. I did find that if you settle yourself right between the two caverns, you will not get agro (though I didn't use magic in any fights). Honestly, these guys didn't link or agro me once during my stay.
They bats in the area were a problem. Since they could kill me, I couldn't use them to build up TP beforehand.
As far as the fight goes, I have to admit that I was unable to beat these things without using my 100 Fists (thank god for reraise earrings); they hit too hard.
As far as self-destruct goes, it wasn't a problem. Again, thanks to previous posters, I had the idea that stun might interrupt it. When one attempted to use it when it was around 50% hp, I hit it with Shoulder Tackle which saved my skin. Any WS with stun should work in the situation.
Was 1/3 on the bomb coal and even picked up my first kindred seal from it.