WELL, speaking as a Bard, I would say that no option, and ALL options, are the best.
What I mean is, if you absolutely cannot handle more than one mob at a time you will need mezzing. No monk or necro can handle that for that mission. You will need bard or enchanter.
IF you can handle 2 or 3 mobs then the extra dps from a monk puller would be more beneficial but you need a slower to do that, and someone, (besides a cleric) who can root a mob away if need be.
Us bards can efficiently split and pull faster than monks, and can mez one from a double pull, so it will be a slower more methodical crawl usually.
MY first advice is DO NOT do a catacombs mission unless you have 6 ppl. Plain old don't do it.
It will be total frustration for your 2 or 3 ppl. Instead pick a static zone or MAYBE a Draniks scar (Historian) mission and sit at one spot and pick off mobs as they spawn or path by. It will be tons easier to get extra ppl to your camp to join you, and it will be tons easier to afk if need be or whatever. If you pick a HOT zone, there may be others there willing to group with you and you will get better exp either way.
Safety is in numbers, and loam drop rates are not so good, so the faster you kill mobs of the appropriate lvl, the more loams you will see.
MY BEST advice is to create a bazaar alt and throw a couple normal bags on him and sit him in the blue section of bazaar with /buyer on. About 3000p should do it for soluble loams. Thats much lower then the going price in the red section but often ppl just want to unload stuff and dont have time to sit in bazaar as a /trader trying to sell their junk for a higher price.
IF you happen to get a few too many loams than you need, just sell those in the red section for a bit of a markup over what you paid, and it will offset your costs some.