Mantis Update

Christmas Eve a friend came over and her two kids took about 5 each off of the original white tree where they hatched. We had put it outside on the porch and I was amazed that they were still alive after being out in the cold...I wonder how they are doing?

I saw one today...up on the houseplant upstairs. I put it there to spread out the mass that was downstairs. Two days ago I counted 10 inside the container with the crickets...now I can't find any. There were also about 10 outside of the container resting on the walls and the top, enjoying the heat from the lamp I have aimed there.  The funny thing is the crickets are doing great and there are now fruit flies but nobody to eat them. I am torn about what to do. Have the other ones been eaten, just died, got out someway? Should I just let the food source thrive in case I find some? Hopefully a few migrated to where they can find a meal and when they come back to the container I can throw them in for a meal?
I know it seems kinda silly...what do I expect to do with them ALL WINTER? I don't know... I wanted at least a breading pair to keep my garden pest free!