Data is done differently. You'll hit Cricket and ask them for the "APN" information. The voice and old style SMS works with just a SIM card change but those other items? Cricket has to tell you which APN values to use.
Don't know APN? Read https://en.wikipedia.org/wiki/Access_Point_Name but that's just going to confuse most. Really, just ask Cricket for the settings.
I am already aware that my AT&T iPhone will accept my cricket SIM card . My question is in reference to iMessage and FaceTime features. Will I still be able to use those from my phone number if I put my cricket SIM card into the phone? Please help.