Custom / Concept, by 
Trigger zones work in 1.23. They just aren’t listed in the JCS.ini that comes with most versions of it. Just add this line to your 1.23 JCS.ini: 246=Trigger Zone |+|Trigger |Trigger|Zone|TriggerID:5|on/off:1|switch:1
Or, heck, just use the converter; if it messes up the triggers, that is a bug in the converter and not an actual difference between the level formats’ or JJ2 versions’ capabilities.
Also, they only apply to the connection that triggers them, so unless the 2vs2 is in the form of four players splitscreening, touching one yourself does nothing for your teammate or your opponents. Test your levels!
(also you spelled claustrophobic wrong)