A gooseneck trailer is always better than a bumper hitch but I doubt you wanna put a gooseneck ball in your L. I'm assuming you're going to pull it with the L. If not pull it with a gooseneck. More stable. Better weight dist and easier to control pulling and backing. Just a thought. If you pull it bumper/receiver hitch wise I"d go with a weight distributing setup.
And definitely get at least tandem axle. Duals on each axle are alot more stable but I don't know that it's necessary. But that trailer and vehicle will be quite heavy. Especially for a bumper/receiver hitch set up.