So... what I would like to know is, what is the easiest way (if any) to continue to top up my kids 1BTC wallets without losing half to fees? Should I just sweep them and start again? I am reluctant to do that as they have their names in the address which I thought was cute.
There is no reason to stop sending to your kids wallets. It won't affect how much you pay in fees. However, if you sent (or continue sending) many small amounts to their wallets, then you might try to lower the cost of sending
from their wallets by consolidating them when fees are low.
Here is an article that describes it:
https://thebitcoinmanual.com/articles/coin-consolidation/