Both the AMS and FRA friday nightstoppers remain there until that sunday on a remote stand and crew positions via LHR that sunday.
About the charters. I wished they would use the aircraft during the weekends and make money with them rather than having them sitting idle somewhere. Just my 0.002c.
On the other hand, they've always stated that their main operation was the focus. Especially now with the crewing levels tight and the good old RJ getting a bit tired they can't take the risk of having crew out of hours or aircraft tech somewhere with disruption to our normal ops as a consequence. I think that once the Embraers are up and running, and crew levels back to normal, they'll get back to charters.
I also read an article about the E190's range from LCY. It states
over 800 miles but fails to mention anything about with what kind of payload.
Private Jets News: EMBRAER 190 undertakes successful week of trials at London City Airport
Usually our MAD's are about 815nm and a Lisbon is about 915nm from LHR.