Well, the thing about comparative strength is that you can't really do it between Marvel and DC. To some extent, all heroes are basically as strong as they need to be, but that's more explicitly true at DC than at Marvel - Marvel stats out their heroes, DC just wings it. Clark has done stuff like helped pull celestial bodies around, which is way, way more than 100 tons, but he's also struggled to hold a train car over his head. Bruce can take a hit from the General without even flinching, or he can get cold-cocked by an ordinary thug. So the only way to get a sense of relative DC power levels is actual trial-by-combat - who can beat who. That puts Thor in Billy and Clark's weight class: Thor fought Billy during Amalgam, and they were evenly matched until Thor pulled the lightning trick, and Thor fought Clark during JLA/AVENGERS, and Clark beat him by a nose.
As for Mjonlir possession, he wasn't able to get the hammer back from Bill during their initial fight, but that was during his "sixty seconds to Donald Blake" period, so I'm not sure if that'd still be true or not. Good point. How the lasso effects Thor is less dubious; if the goal is a beat-down, the only power that really matters is the pliability and unbreakability (well, also she can use it to dismember things, but she's highly unlikely to do so to Thor, and really the only relevant thing is whether she can get it around him in the first place, since restraint is as good as removal), which traits don't really care who they're aimed at.