What is the ruling on adding the phrase "in the worlds" to the Abrahamic prayer (Salat al-Ibrahimiyyah), and what is the ruling on adding or omitting the conjunctive "waw" in the Tashahhud, and does that invalidate the prayer?

The addition of the phrase "in all the worlds" at the beginning of the Ibrahimiyyah prayer is not established, but it is established at its end. What you have uttered does not affect the validity of your prayer, and it is obligatory to adhere to the established wordings without addition or omission. The addition of the letter waw (و) in the tashahhud does not invalidate the prayer as long as it is an error, and adhering to the transmitted wordings is better.