Felix and Fernandes haven't done anything outside of the Portuguese league to warrant a move to a big club. The sums being talked about are also ridiculous due to those reasons.
Ruben Neves according to regular observer's of his club has been underwhelming in the EPL and there's ample evidence. Him playing crap again at a good level isn't a surprise.
De Ligt and Sancho have performed exceptionally well in the Champions League and The Bundesliga respectively in the season just gone. Both competitions are far superior to the Portuguese league, and I don't mean to disrespect the Portuguese league by saying that. So even if they did have off games tomorrow, it wouldn't be a big deal.