A Cheque requisition can also be attached to a vendor invoice where it is necessary to alert Accounts Payable of any special instructions pertaining to that invoice, such as special mailing instructions or special payment requirements (ie wire transfers).
To get more traditional mortgage loans, your credit scores need to get above the 620 to 640 range. If you want to get the best interest rates, you need to raise your credit score into the 740+ credit score range.
If we had to name the absolute lowest credit score to buy a house, it would likely be somewhere around a 500 FICO score. It is very rare for borrowers with that kind of credit history to receive mortgages.