As per CIC, the only valid job offer is one which is supported by a positive LMIA.
All other applicants will need to provide POF which, for CEC applicants alone, can include monies in the bank along with other supporting evidence including work authorization status, offer letter mentioning salary details, pay stubs, T4s etc. Upload an LOE explaining that all of these are sufficient proof that you can take complete financial responsibilities for yourself and your family in Canada.