I do not know if it is possible to spill enough antifreeze to get some into the cylinder and cause a hydro lock. Check your air cleaners, if they are wet with antifreeze then the dealer did get some into the engine. This could easily damage the engine.
I never measured the conductivity of anti freeze to see if it can short things out. My guess is that it is conductive enough to drain the battery and cause other electrical issues.
If you think you have gas leaking into the engine, Pull the plugs and then turn it over. if there is gas in a cylinder it will spray out the plug hole and not hydro lock.
Be very careful you do not ignite the gas spraying out of the engine.
Depending on where the engine stopped in its rotation relative to the cylinder with liquid in it has a lot to do with what happens. if the hydro lock happens as the first piston is coming up with only starter power, it will stop the starter with likely no damage, If a cylinder fires Before the cylinder with liquid comes up on compression stroke then you are likely to break something as now you have both the power of the starter and the power of the cylinder that has fired as well as the inertia of the rotating assembly all hitting that one point for a hard stop. All that energy has to go somewhere.
You said you had gas in the oil, are you sure it was not antifreeze?
I'm not sure just where to start, You may have multiple issues which always makes it harder to diagnose. You seem to have symptoms that should be completely unrelated.