Noctua’s NF-A12x15’s are pretty good for slim fans. They also have a Chromax.Black variant. You will be limited to 120mm, though, as they don’t make 140mm slims, but that should be fine.
You can also check this SFF spread sheet for other slim fans if you can tolerate higher noise levels.
Sorry I’m not terribly familiar with your case. But my first thought looking at your pics is that if you pop the front off you might be able to mount the fans in the gap between the front mesh and the frame. If my eyes deceive me and that is not an option you could build a spacer to go inbetween the front panel and frame allowing you to mount the fans there. that would allow plenty of space for your card.