Cabaye and Clasie both play in Bentaleb's position/role. Bentaleb is a better player than both of them, IMO. Or at the very least it's not a role in the squad/team we're looking to buy in, as if you're talking the need of backing up the recycler/play-maker position, then we have Carroll back in the fold and Winks.
Imbula. He could have been an asset, but we don't know what went on with him. He was linked with a lot of big clubs, like Inter, yet ended up at Porto. His father made some derogatory comments about players moving to clubs like Chel53a and ruining their careers, so it's possible that only Porto gave him the guaranteed first-team starter assurances he would have wanted. Any midfielder coming in with us is going to have to fight to keep his place, as we will want to give Alli, Winks and others game time.
Suarez, well that is a strange one on your list. What does he offer that Stambouli didn't do you think?
Ayew. What does he bring that Chadli doesn't? He's not got the explosive pace that we appear to be going after? We have quite a few wide-forwards with moderate pace who get forward and score the odd goal. So what? It looks like what we're really after is explosive pace and goal threat that can also play upfront. Don't see how Ayew fits the bill here. Konoplyanka- Loads of clubs looked at him and passed. Why do you think that is?
Cabaye and Clasie both would replace Mason as all-around midfielders capable of creative forward passing, good tackling, and in Cabaye's case, he would've given us a player with lots of high level experience and end product (excellent set piece taker). Let's see how they do at Southampton and Palace this season and we can revisit this debate.
As for Suarez, he is a far better, more accomplished player than Stambouli. A better tackler, a better reader of the game, a better passer of the ball, and lots of top level experience having played a huge role in winning the La Liga title and being one of the unsung stalwarts that helped them nearly win the CL.
As for Ayew, he has far more pace than Chadli and presses the ball better than Chadli. He has way more end product than Andros Townsend (2 goals and 1 assists from open play in the last 2 seasons combined), so having added him to Eriksen/Lamela/Chadli would've given us options across 4 competitions and in the event of injury. But again, he'll be at Swansea, so we can assess this debate again during the season.
Konoplyanka ended up at Sevilla. They've won the Europa League the last two seasons and have been one of the shrewdest operating clubs in the transfer market in the last 3 years. Don't think that's evidence of some type of red flag surrounding Konoplyanka, but instead speaks to the fact that they see him as someone who can help them compete in the CL and become a top 4 team again in La Liga.