Hi Tristan. What a great looking helmet and E11 blaster they look awesome.
In a quick view , what I can see that will be a block for higher levels :
1- E11 Blaster: Even though it look great , there are some small details that we didn't see on screen and you will need to address :
Ammo Counter
CRL for L3- The blaster may have minor weathering or base metal exposure however, T-tracks and grips shall be of a black plastic appearance with no silver/metallic weathering allowed.
Although in some counters the brass could be seen, in this one it does not look like weathering, (it is a perfect square). You may be able to paint it black and then rub a little before it dries completely, and thus give it the " weathered " look. Also it would be located forward as the reference images.
References
2- Helmet : As EIB and Centurion are an add on to the Legion standards, it has to be Basic approvable. Those scuffed marks looks great from a prop replication point, but aren't for what was intended and not what we saw on screen when things are moving, and thus not allowed on a Legion approvable costume. You may want to check the EIB and Centurion application Threads and see what we look for.
Rerefences
I would also suggest to trim a little more the extra material in the Left Eye
References
This was a quick check and more details would be pointed in a EIB and Centurion Review. keep it up