Any animal that can scratch and bite is an issue for children in your care (and their parents). Some may also have allergies (eg to cats - which could include fur, skin / dander and saliva allergies, or even to ingredients in pet food). It doesn't exclude having them, but needs to be taken into consideration and managed appropriately.
The animals are also at risk from the children, who are likely to prod / poke them and feed them unsuitable items. Rabbits are also prone to stress - loud noises, sudden movements, being picked up roughly, being dropped, etc can all affect them badly. Screaming kids rushing around directly outside a rabbit pen and dropping leftover lunch through the bars isn't going to be good for rabbits. They are best kept safely apart and treated with mutual respect.
Giant rabbits need loads of space. Rabbits are also much happier with their own kind and should not be kept alone. Standard shop-bought hutches are often barely adequate for small rabbits, and are certainly not big enough or robust enough for giant breeds. Wendy houses or sheds work well for rabbits, although a Wendy house may be too small for giant breeds. Aviary panels can be used to make an attached walk-in permanent run. You can also easily adapt an outdoor dog run with integral kennel to suit rabbits. Local shed makers often list them, or you can get second hand ones on eg eBay.
Weldmesh will keep dogs and foxes out (as long as they can't dig in, or the rabbits dig out), but you may need to double up with a smaller mesh to keep curious cat claws out / stop a rabbit head getting stuck in larger mesh. Cats are persistent beasts when there's something of interest to them, and they are prone to swipe through bars / mesh at caged animals. Those claws can cause quite a lot of damage to the thin skin of a rabbit with a casual swipe, and it's expensive and stressful to get the rabbits treated.
Having giant rabbits indoors is also an option, if they can safely have the run of the house. All rabbits are likely to chew (wires, woodwork,etc) and dig (carpets).
