So here is what I've learned so far. Correct me if I'm wrong.
You can't wet vent a fixture into a waste stack of another fixture unless they are on the same floor. This removes the option of tieing into the 2nd floor kitchen stack that is one stud over from the new washer I'm installing.
You can wet vent a fixture into a waste stack when they're on the same floor, but wet vent part must be one size larger than minimum required. The CI pipe for the first floor kitchen sink is 2" diameter.
Is the current 2" diameter the correct sizing for for a washing machine and kitchen sink? The Washing machine would tie into the 2" pipe above the sink. Do I need to replace with larger pipe from the washer down?
Thanks for the advice.