If one account is suspended then you are not usually allowed to sell on any accounts even if one has been established for some time.  I have more than 5 accounts with one isp but did have to use a mobile number for the last one I opened.  I am not surprised they suspended your accounts if you tried opening them in other people's names even if they were your offspring, had you opened them all in your own name they would probably not have trggered an enquiry at all.

I would not try listing on your old account without getting the all clear first but if you do then it is very essy to transfer the listings from one account to the other as long as you have saved a backup file. Just click on the link to import from backup file then select the correct file in your bavckup folder and it will import them.