Why is van Reggel wrong?
because "van reggel?" means "is there morning?"
Completely different! Good thing I asked. Köszönöm Szépen!
Don't mention it!
Why is there no t on the end of reggel like usual?
Because in this case the "reggel" is the subject / nominative case. The extra 't' is when it is the object / accusative case.
Why is reggelt van lemme guess its a plural?