I dont know what the score is but I would like to throw in 2 points for NO POLES! Good postings here (the ones against poles
) but there is one more aspect not covered sofar and that is your own poles. I vote for both of you dropping your poles. I have over 15y of teaching and I have two kids of my own and I have never used any poles myselfe with kids as beginners up to the level where they are alredy dropping the wedge and comfortable enough to turn in a wedge or parallel at any desent speed and in any tricky situation. Dropping the ski poles for safety reasons is not a lame excuse, it is not only ture risk managaent, its also highly practical.
Also, the kids need to learn how to stay in balance and turn by using their skis. If you put your hands on your knees you isolate any kind of rotational movements from the rest of the body and once you know how to pressure that outside ski you can let go of your knees and grab ski poles. Both of my kids started on nordic skis at 2y and alpine skis at 3y of age. They both progressed differently and the 10y old got his first poles as late as 7 or 8 years of age. By then he was alredy a great skier for his age. The younger started with ski poles last year as 5 y old but he was alredy then in a racing team with much older kids.
Poleplant!!! Forget the poleplant if you are 7y old and a beginner. Kids use their poles to move forward on flats, to gain more speed wheter they need it or not or to hit and poke objects, themselves, each other and the instructor.