I assume you are talking about gaps that will be visible from the outside.

Mixing wood dust with wood glue like Triton or any PVA glue is the worst of the possibilities you mentioned. It leaves a mark that is impervious to the resin, so it tends to look quite different.

Are you aware that the wood dust mixed with resin turns much darker than the wood that the dust came from? If you want to get a good colour match, you may need to experiment with different mixtures of wood dust from the strips and some from much lighter timber or even flour from the kitchen.

If any of the gaps can be filled with a sliver of timber, that is sometimes a good solution.