It is next to impossible to authenticate a clasp from pictures, but I have several concerns:

The bend appears too extreme
What's that gap under the (very thin) buttons in the 4th picture
Is the etching straight?
Finish looks off

 

I did find this link, which looks like the push buttons are thin like mine... https://www.authenticwatches.com/omega-planet-ocean-deployment-buckle-94522019.html#.XTEuHpZlDDs

 

I won't (and can't) give you an opinion on whether the clasp you bought is authentic, but I will post some pics of my clasp (ordered from Omega through an authorized Omega dealer) for comparison and give a couple of thoughts.

First, here are some pics I took of my clasp:

Second, to answer your specific questions:

1. My pushers appear very similar, if not the same, to the pushers on your clasp. The thickness seems correct.
2. It's difficult to tell from comparing the pictures because of differing angles, but the gap between the two halves of your clasp seems a little bigger than mine. That said, my strap is not attached to a watch. Your strap is under tension, which may be creating a bit more gap. My clasp also has a slight bit of play when closed.

Finally, here are my own thoughts on the comparison:

1. Compare our first pictures. My clasp has a small, raised bump underneath the word "TITANIUM" while yours does not.
2. The dimple is cleanly above the word "OMEGA" on my clasp. On your clasp, the dimple touches the E. This clear difference and no. 1, above, give me the most concern.
3. It could very well be the lighting, but in some of your pictures the finish on your clasp appears different. Mine seems to have a more satin finish, while yours appears brighter, if that makes sense. In addition, the embossed lettering and logo seems cleaner and more precise on my clasp than on yours, particularly the Omega logo.
4. It's very difficult to tell from the different angles, but in your first and second pictures, the gap in the forked part of the clasp underneath the word OMEGA, looks different from mine. Specifically, the round notch at the bottom of that fork looks like a slightly different shape (may just be the angles) and the gap where the fork comes back together seems much greater on your watch than on mine.
5. The part number appears the same. It's difficult to tell from your pictures, but the numbering "54" and "HJI" underneath the part number appears the same.
6. Underneath the Omega logo in the last picture of your clasp, there appears to be some extra metal next to the strap, which doesn't appear on mine.

Good luck and hope this helps. I'll be out of town for the next few days, but I can try to answer any other questions you have on Monday.

 

It may be the photos aren't great but the finish on the edges of the inside part of the clasp (which wouldn't be visible when closed) looks a bit rough. I have an omega clasp and the finish on all parts is faultless. The metal looks unfinished in places. It also depends where you got it and how much you paid. Ebay, £30 you can pretty much guarantee its a fake. £200 with an omega receipt its probably just the photos and youre good to go.

 

I'd say based on comparison to yours, there are some inconsistencies.

1) the alignment of the Omega logo, the word titanium and the part number are all slightly off center in your photos - not sure if that's the camera angle or how it actually is. I'd measure that just to be sure
2) the part where Omega is engraved is perfectly flat on both mine and TLud's photos. On yours it doesn't appear to be
3) on ours, I noticed that the curved part of the clasp is quite a matte finish, but it doesn't quite look like that on yours

Here are photos of my titanium clasp for comparison:

Good luck! Hope you get this sorted out.