Agree Oliveira fills a huge need as a true 8 and better suited than Augusto next to Omar but I have not seen enough to judge his full skill set.
I think when you see this style one of the wide mids drifts inside toward the center of the field - Limnios would be well suited to the role when he plays (imo his future is as a modern attacking RB). The other wide mid gets high and cuts inside to act like a second striker (almost exactly what Biseswar does anyway when he plays as a LM). Pelkas would drop a bit behind them and play the '10' and your fullbacks become your wide midfielders.
Assuming Fereira does ANY of this, then it could look similar to Gregg Berhalter's system from the Columbus Crew and now USMNT. This tactical analysis could be pretty close:
https://www.massivereport.com/2017/8/23/16191846/tactical-preview-la-galaxy-faces-crew-sc .. If Vierinha comes back 100% he and Matos are perfect for this attacking style.
Would work against many teams but I agree, not convinced it works against Ajax.