Mike mentions having a brother in law being a Lawyer. This would indicate Mike having siblings, but would go on to be clearly indicated as an only child.
The Bunker family physician is said to be Dr Ferguson. Subsequent episodes clearly indicate that Dr. Shapiro was the Bunkers' long-time physician (A Dr. Nelson is also mentioned in later seasons).
The "bicarb" Edith gives Archie is just a glass of clear water.
When Archie decides not to eat after only taking one bite of food because the meat is too rare, Edith clears his plate AND her plate. But she just served herself helpings of her own food and just started to eat dinner so there is no need or reason for Edith to clear her plate.