Interest Check: Marvel Noirverse
The choice of system is perhaps the most important thing you can do to determine if players will come (the purpose of this thread). It's in this context, I'm making these comments. They are just my views. I suggest we don't 'argue' about other people's views or we will hijack the thread, but just express our preferences (no one will successfully change someone else's views on systems). We usually want to say 'why' to help the OP make decisions.
My personal negatives on systems:
No FATE for me :) Along with PbtA it's in the list of 'too terrible to even contemplate playing again' list. Fate makes all characters identical, PbtA makes them all unable to do anything else their ultra specialised thing without crippling other players... YMMV.
GURPs is in the, for me, 'too boring to really want to play again' list but isn't terrible.
I will observe other people say they have had good experiences with those game systems. A good GM can compensate for most game systems, and different people have different objectives from a game system. (I've played them with good/great GMs though, and even there the comments I made above stand)
My positives on systems
The classical RPOL game for super heroes is Mutants and Masterminds. There are many of these games on RPOL, and they usually work well. There are other game systems that work well. The Marvel Heroic Roleplaying for example is great/superb for playing Marvel characters but is no longer in print. I've recently taken a look at Prowlers and Paragons (or the other way around) and that looks a blast. I've no experience with the other 'specifically Marvel' systems except the very first one. I'm told people like them.
Freeform works OK if you aren't planning on much combat. Again that's my perspective, other people like freeform for everything. Since combat is a speed bump and game killer in RPOL prefering social / investigation to combat works very well. And outside combat freeform is in many ways the default system even when there is a game system.