If you put a request in writing as HaoZi said requesting difficult child be "evaluated for special education services including but not limited to THOROUGH academic, psychological, behavioral, Occupational Therapist (OT), and Speech evaluations", they legally CAN'T refuse to do the evaluations. Doing it this way and phrasing it this way will put FEDERAL timelines in place and there are repercussions if they don't do it. You need to be specific in your request and send it so you have proof and you need to send it to the principal AND the Director of Special Educaion.
Also, get an advocate ASAP. The sooner you get one on board, the less strain it will eventually cause YOU. Good Luck.