All theoretically possible, though bury your ship on this planet and you may well never see it again.
It IS odd, Wentar, yes. But if it was a simple as him not being here, your intuitions would have said so earlier. I indicated when you were in orbit that this is the right place (amongst its many uses, the Force really helps advance plots...)
I don't suppose we can discern any pattern in this area, trees/landmarks/etc? I'm thinking maybe this weird area was altered in a way that points to Lennah's hiding place and then covered up to look like an unremarkable piece of land
Essentially, if you know what landmarks to look for, you can find your way around. Possibly put in place so Lennah himself doesn't get lost in the swamp.
You don't have specialised surveying equipment and the like, no.
Nah it's nothing like that, Wentar. A cloaking device, as Denz suggested, fits your feeling perfectly, as that would mean the apparent unremarkableness is a fake.
The area is a bit vague to have a precise centre, Denz.
You can just keep canvassing the area until you find something, but that takes more time, is all.