Is it safe to connect lithium protection circuit to positive terminal of the battery?
The original circuit in the DW01 data sheet is this: -



And the biggest problem with your circuit is that when putting N channel MOSFETs in the positive rail, you won't be able to turn them on from the control signals OD and OC. Those signals in the normal circuit (immediately above) will rise positive above BATT- and activate M1 or M2. To activate either of those MOSFETs in your new circuit, the drive levels have to rise higher in voltage than BATT+ (by probably at least 2 volts if not more) and there is no facility in the DW01 chip to achieve this.