The guppiees probably will las the cycle
BUT
They may not be too healthy. It is really important not to overfeed.
When females are 'pregnant' they become larde abdominally and should have a black spot internall ant the abdomen rear. When the girls start seeming restless they are about to give birth.
If you cycle with just those few small fish, the filter will not be very high capacity so its almost like you will have to mature it further if you plan to stock the tank any more. May only thake 10 days with good water changes.
Really, dont overfeed.