Definitly LN. I mean just compare how Clayman is portrayed in WN and how he is portrayed in LN. In WN he is essentially just a cocky, overconfident two-dimensional comic-book villain who did nothing but spouting cliché lines. In the LN he receives a lot of proper characterisation and his connection to the moderate troupe, Kazaream and Yuuki is much more elaborated upon. There is even foreshadowing that someone completely unknown, other than Kazaream and Yuuki and the troupe, has been manipulating Clayman unknowingly. I am refering to the scene where Laplace asks him "this plan really comes from you and not someone else?"
Rimuru is also shown to be much more careful about revealing his powers (or rather the fact that Gazel is advising him to do that, unlike the WN). IIRC in his "fight" against Milim he did not really use the Spatial Hax he got from Vow/Convenant Lord Uriel. I think between his battle with Milim and his battle with Clayman, the Demon Lords by now most certainly should know that Rimuru is an "awakened" Demon Lord (he didn't really seem to tried to hide that from them anyway), but they only saw Gluttonous Lord in action - and perhaps they might deduce the fact that Veldora manifested as a Ultimate Skill within Rimuru, but Uriel and Raphael should have been successfully hidden from the Demon Lords, aside from Milim maybe just for being aware of the before&after of his capabilities unlike everyone else, so she might have notice Raphael - not like she'd ever sell out her BFF. The general public? And further-away countries? Rimuru made them believe that he is just a Demon Lord Seed. That's a good reason for the western council and that idiotic prince to be underestimating Rimuru personally later on if that still happens, unlike the WN where it seemed just stupid instead.
I am not sure whether or not Veldora misremembering Ruminas is a good or bad thing. Imagine the commotion that could have happened had her true name been revealed to Rimuru. Based on the side-stories she probably wouldn't try to go after Rimuru himself due to his connection with Chloe, but it might have been a different matter if Rimuru had been aware that she has the same name as the western church's god. Will have to wait for vol. 7+, since appearently that's where things really start diverging plot-wise, e.g. Hinata supposedly isn't brainwashed by Yuuki but gets tricked by the church into believing that Rimuru wants her head or so I heard (the side-stories also corrobarate this).