I don't think these two teams can give Real Madrid or Barcelona a hard time. Real Madrid and Barcelona will win these matches without any problems. Also, since the situation is at a critical level in the league, I think Real Madrid will play the matches more focused and win most of their matches. The Arsenal defeat may have been a shake-up match for them. Perhaps such a defeat was necessary on the way to becoming a strong Real Madrid again.
Indeed, Leganes and Alaves are struggling to collect points to get out or stay away from relegation but I'm not sure if Real Madrid and Barcelona lose points because in fact both teams are also competing at the top of the standings well that means they won't waste any match. On the other hand, Real Madrid need a win to boost their confidence as we know they lost in the last 2 matches including one defeat in La Liga last week, this means that Real Madrid has a greater chance of winning. There are no interesting matches this week in La Liga except between Real Betis vs Villarreal because both teams are chasing points to secure a place in the top 4.