IMEI number shows what information

No one can read your texts if you deleted them. Now in all honesty your carrier/service provider may have the information, since your texts and calls are through them. I can't say for sure. And the person(s) you were texting would have them and could share them if they chose to with anyone they chose to. However it is seriously unlikely that anyone could get them off your phone and on top of all that, the IMEI has nothing to do with it.