Yeah, sounds like you might need to be careful with connecting fuses depending on where you are. But if you're allowed to, sounds like yo'ure fine with your method of ignition.
As far as securing, i personally (and know a lot of guys) that use Liquid Nails...if you don't know what it is...basically just a really strong glue. This year i used both liquid nails and duct tape. Either or should be fine...cakes shouldn't go anywhere (just connect them to a board)