Excellent points! Thank you.
And artchill reminds us that Jews who must eat on YK must say birkat hamazon if they eat a meal with bread and include Yaale v’Yavo. If you normally sing Shir Hamaalot on Shabat and Yom Tov you would sing it on YK as well. The Yaale v’Yavo for Yom Kippur is not usually found in bentchers but can be found in any YK machzor in the Shemoneh Esrei.
May all reading this have an easy fast!