SLEs an LIEs can superficially be quite similar. I've had my fair share of "mutual interest" with IEIs too (although probably victim-victim is much harder to start when compared to aggressor-aggressor). I'm not really sure if I'd consider ESIs hard to get when compared to IEIs, since the latter tends to be "+ infinity" wrt that characteristic
IDK though I think an SLE-Se can get along sufficiently well with an ESI, although of course they won't provide each other any - however they would probably be OK if they had a certain number of dual close friends.