Preparing chicken burgers for sous vide then freezing while keeping shape
You're missing a binder of some kind. You're adding some fairly moist fillings to ground meat, which is already moist and whose structure has been destroyed. You need something to soak up the juices of your burgers as they cook, and that's the purpose of the breadcrumbs you're missing. I know you said you would prefer not to include them, but that is the easiest and probably best solution. Egg (or just egg white) is another common binder, but with all those already-moist ingredients and no breadcrumbs, I wouldn't recommend it.
However, there are a couple of other options you could try.
You could try adding a few tablespoons of cornstarch or potato starch to your meat mixture. That would have the effect of thickening up juices as they're released during cooking-- if the temperature is high enough for the starches to gel.
Another option is more of a technique (which I confess I've never tried, so I can't personally vouch for its effectiveness). This recipe uses no binders, no breadcrumbs or cornstarch at all. Instead, it calls for a portion of the ground meat to be fried off beforehand and then mixed in with the rest of the ingredients. The mixing in this case is actually kneading; the recipe specifies that kneading very very well is key to maintaining the structure of the finished patty.
In any case, as far as the patties being misshapen from the freezer goes, consider making an attempt to rearrange a flat spot for your burgers, at least when you first freeze them. Once they're solid, they can be moved to a more convenient spot in the freezer.