Yeah it is true about what happened in UEFA Europa League and that might have an impact on Real Madrid squad which Ancelotti took it on consideration I suppose.
Injury and absence of Tchouaméni can affect Ancelotti's choice for Real Madrid squad in the final but it will not change his choices for the eleven debut players too much.
That defeat of Bayer Leverkusen could boost the confidence of Borussia Dortmund but we all know that Real Madrid is something else in UEFA Champions League. We are not talking about the classic Real Madrid in La Liga which could lose points against a team weaker than them. Here in Champions League they kick big teams like Bayern Munich, Manchester City, PSG and intimidate them at the same time regardless how the first leg score ends. Since this is the only and last match, I suppose they will play it in a serous manner.
Two shocked defeats of Leverkusen and Manchester City are big warnings for Real Madrid before the final. Assuming they start with same players for their squad, they can have different attitude for the final after seeing two shocked defeats with stronger teams are victims. They will debut the final match with more carefulness and it will minimize opportunity for Dortmund to make a shock win in the final.
I hope the best for Dortmund and hope that Reus will have a big title with them before leaving Dortmund or at least they will make an exciting match before Real Madrid can make some twists and win it eventually.