No it's not. It's created by a different gland in the body and stored in a completely different region then the bladder. Some urine could be release and studies do show trace amounts but the vagina has trace amounts in general from splash back during urination. Not enough to be considered "pee" just particles (very small amount, tiny even) Most women have trace particles of feases, urin and blood in their vaginas.

A woman's 'cum' has been tested to see what it consisted of. And it was diluted pee.

Not technically no, but the fluid actually does pool into your bladder before ejaculation, so you ideally should make sure to pee before intending yo squirt otherwise it WILL mix with urine lol