@Clooud
Initially, Lalo was going to control Arata by force, by saying "I could easily destroy this bunch of trash around you", and Arata pretended to accept that, but then Arata suddenly calls out Lalo's bluff by saying that Lalo is actually alone and has no forces. So then Arata's men force Lalo to kneel and begin to restrain him, proving that it was indeed a bluff. So now it looks like Arata is going to be the one to control Lalo.
@RapidLord
I'm leaning towards it being an unfortunately positioned sweat drop, mostly because "him hearing the news" and "the tear drop" happen in the same frame, which seems too fast. But if there are any referees that he would be attached to, it would likely be one of the older ones like Ikon.
I don't think Nowa Jr is the other masked guy, because referee douji snuck into the building in his regular suit back when Robert K was around. Also Fukurou has lost his membership multiple times as far as we know, so he's probably had many different exclusive referees, Nowa Jr and Fukurou probably aren't too close as a result.