So I got the latches and tubing for finsihing up the job. The latches are simple toggle latches, about $1 each, spring loaded. The catch is mounted to the lid and I used a small piece of copper wire to extend the catches reach to secure the lid.
The gasket it made of a 3ft length of 3\8″ silicone tubing. Isplit the tubing length-wise and it just sits on the lip of the pot, easily removed for cleaning.
The airlock sits in a 3\8″ grommet in a hole I drilled in the lid. It looks very well sealed up, first time I used it will tell.