EI-REL/REM/-REO/-REP are the craft they have from their order for new ATRs from a few years ago - the final ones were never delivered.
EI-SLx are all former Delta Connection (I think) birds which do generally seem to be in a mess.
As goes the 42s - waaaah. Think one of them has a new interior, but they're horrendously ancient and really need to go, asap.