compost in incinerator bins.

[T-oddity]

You say that you will be using grass cuttings, on their own they will create a big slimmy mess, do you intend to add anything else to the mix?
Composting works best with a good balanced mix of greens (grass clipings) and browns (High carbon material like straw, woody stems etc) and in large enough quantities (about a cubic metre) to build up heat.

Rats will only turn up if there is a food source, such as kitchen waste.

I compost everything and do get rats usually during the winter when the heap is at its coolest, but I use a walking compost heap system that continually disturbs the rats.