Using the official website, this is where I plot each of the 32 players on the 1st team page based on UEFA definitions.....
List A - Vicario, Kinsky, Porro, Udogie, Romero, Danso, VdV, Dragusin, Vuskovic, Takai, Palhinha, Bentancur, Bissouma, Sarr, Bergval, Kulu, Kudus, Yang, Gil, Solomon, Odobert, Richy, Tel
Assoc - Spence, Davies, Gray, Maddison, Johnson, Solanke,
Club - Austin
List B - Devine, Scarlett
Apart from over age Mathew Craig, I believe all of our U21 squad on the website could be put on list B.
Based on what I see, we have 23 list A players for 17 places. However, that goes up to 25 as you can only use 4 association trained slots in a UEFA squad. So 2 would move over to List A as well. I guess we can bring it down to 24 if we exclude Maddison for first half of the season.
What is the real gap? It's obviously less as we wouldn't name Gil or Solomon. So that is down to 22 and you could then removed Takai, Yang and Vuskovic to bring it down to 19.
Even if we sold Bissouma there is still one of our senior stars who will miss out. This is before we make another signing.