I have taken 6 cuttings from last years outdoor cr...

To reveg a plant you don't have to do anything over the top. Provide a veg period length of light, whether you're an 18/6 person or 24/0 it doesn't really matter. It doesn't really need to be intense light, low light conditions are fine as long as it's enough to spark photosynthesis. You'll also want to go very mild on your nutrients until it starts showing new growth, think the sort of strength/composition you'd use on a seedling. On a larger plant I'd also suggest trimming back the root ball but that's probably unneeded for cuttings.

As it was mentioned before, cutting off buds will not stop flowering. I read that if you want to return a photoperiod plant into vegetative state, you have to interrupt night hours with light. Several interruptions for 15 minutes during dark hours (every night until you notice difference) should do the trick. If plants are outside you still can set on timer some garden flood lights. This method is used by industrial growers on other plants, and usually as preventive method (to prevent early flowering), but there are some findings pointing that it works on cannabis too. You should not forget that flowering in photoperiod plants is triggered by number of dark hours. If your plant started to flower early that means it didn't receive enough light during day. So, the first thing you should do is to provide your plant with adequate number of light hours.

Cutting the buds off won't stop flowering, the plants are full of hormones telling them to flower. The only way to stop them flowering is to have them under lights at 18 hours of light and 6 hours of darkness (18/6). 18 hours of light will stop the production of flowering hormones. Just leaving them means they will finish their flowering cycle and then die.