You can get Snappi's from places like Big W which you use in plac of pins, they are like a T piece that holds the nappy together, althogh I am not sure how they work on FF.

You can get a range of covers online that can be used to hold a nappy on rather than pining it. The best ones are ones with the gusset legs, as they help contain the poo. Some brands to look at are Motherease Rikki, Bummis, Bambino Mio (I am sure there are more.)