This one is hard because you only have great knives in your list.
i have a PM2 s110v, a black blade/black G10 Para 3 and a Spydiechef, I had both large and small DR Griptilians and I am waiting for the next batch of Atom to be released... I understand your pain in choosing between all of them
I am not the biggest fan of axis lock. It is a proven and fun to play with mechanism but I don’t like the disassembly. So the Hogue will be my last pick
the Para 3 is great but I had to buy a custom clip to improve the carry. I like it now but this extra cost is boring. Unless you cannot carry full size blade I would dismiss this one even if the compression lock is a very good lock.
PM2 is great. I like the larger handle in this one as it gives lot of options when using the knife. The compression lock has been great on all the versions I had. If you want an EDC capable of some abuses I would pick this one for sure. It is the most versatile in your list.
Both Para 3 and PM2 doesn’t really require exclusive steels, s30v, s35vn, s110v and Maxamet are good options already IMO
the Atom... I don’t have this one but I think it shall be an “urban” alternative to the PM2 in your list. There is a lot of buzz around this knife at the moment. It shall be deserved but I wait to see by myself.
It has plain lines, nothing new into it, just better done than similar production knives. It comes with a good steel and a deep carry.... if you want a light EDC you shall pick this one
I think I would pick the Spydiechef. The frame lock is less fun than the compression lock and it lock ugliest than even the PM2

but the new CQI version. Makes it almost rust proof and the idea of a knife you don’t need to care of is very fun. The knife is very well done and even if it is very thin it has still a good grip. It feels like the child of a PM2 and a Sebenza. It is easy to disassemble and it feature a low carry wire clip. Very good at food prep and a lot of tests praise LC200N for EDC.
if you look something more original than a PM2 or an Atom it may be the one to go.
As a summary depending of your need:
- small blade, go para 3
- capable of outdoor and abuse, go PM2
- modern urban EDC, go Atom
- no maintenance / rustproof EDC, go Spydiechef