In regards to the identity, can someone tell me what it is to be Egyptian?
I'm hesitant to answer, only because I'm trying to understand the point of your question.
Today, being Egyptian holds a genetic diversity similar to saying "being American." Sometimes some Egyptians look very Mediterranean, i.e. share similar features with Greeks and Italians, and some Egyptians seem to share features with Arabs, and then you have the more African/part African (i.e. darker skin, coarse hair, etc.) looking Egyptians. Pretty much sometimes, you see someone and you are surprised to find this person is Egyptian, while other times you may believe someone might look Egyptian to you, while in fact he/she may be Spanish, Greek, Italian, Israeli, Iranian, even Indian.
So what does it mean to be Egyptian? I don't know...speaking in an Egyptian accent of Arabic may be one clue, tracing your close ancestry to some time back in Egypt? I'm not sure what your question alludes to specifically.
Here's one litmus test, if you see a dude named Mina...definitely Egyptian, specifically Coptic Christian (because as far as I know, only Egypt has Mina as male names).