The Men in Black have knowledge of about half the other Sony-created movies/cartoons and their characters, creatures and equipment.The MIB (in the cartoon-verse) keep tabs on the Ghostbusters, provided covert assistance to HEAT and Zilla when they fought against the psychic aliens, they've dealt with N-Tek (though after N-Tek's government funding was cut off, they have doubts as to how long Max Steel can keep operating), Section 13 has met with them concerning various issues, they have their own dragon scale (and in turn have met with Quetzal, and keep tabs on Max and Emmy), have investigated rumors of a strange board game wreaking havoc in New Hampshire, and have also learned of the existence of a small, anthropomorphic mouse living in New York with a human family. However, since most of these assorted phenomena aren't aliens, they normally don't deal with them (though they're still investigating where exactly Dragon Land is- pocket dimension, another planet, floating hidden island even- to determine if that would fall under their purview).
- More credence to the theory is that XGB, MiB and Godzilla all shared an animation style and location (New York). Perhaps if XGB had lasted beyond one season and/or all three shows were on the same network, there could've been frequent crossovers.
Jeebs is a symbiote who merged fully with his hostHis blobbiness seems really similar to what we see of Troy's hosts. And we know that after 24 hours the host and the symbiote apparently "become one". I don't think anything we know contradicts this, so why not?
There are still non-MIB humans who remember aliens after the Series Finale.Zed just used the neuralyzer in a world-wide transmission to erase everyone's memories but there might be people who weren't watching it or wore sunglasses.