You're right about the maxilla -- to some doctors, paranasal implants are the cosmetic equivalent of a LeFort I. It adds convexity to all the same areas and can lift the upper midface as well in the same way a LeFort I can by providing greater soft tissue support.
Infraorbital rim implants are for people who have a negative orbital vector -- their eyeballs protrude out more than the malar eminence which in more significant cases is unpleasant aesthetically. Skeletal deficiencies in this area also can cause a negative canthal tilt or downturned eyes and scleral show which are both due to insufficient skeletal/soft tissue support around the eye area.
As for me, I simply got a standard hyaluronic acid filler (juvederm voluma) that was injected into the soft tissue under my eyes and around my nose. Ideally I would've gotten HA paste or something. The results won't last but like the original poster, I wanted to see how I would look with a fuller midface and see if that really was the key to my aesthetic issues as I thought it was. All of my cephalometric angles are normal except for the ones involving my maxilla -- I'm a skeletal Class III. It gave me a better midface, added dimension to my face in general, and made my cheekbones look sharper. My dysmorphia was very severe before I had the fillers and now I feel incredibly liberated and no longer obsess about being ugly 24/7 like I used to; for me there was a great psychological benefit and I do not regret it at all. My advice is to consider trying them even though they won't perfectly mimic having a LeFort III or I done, they give you some idea of the changes you can expect and can maybe help you breathe easier for a while.
PS- no filler was added under the nose. The fuller facial hair is masking how recessed the region under the nose is -- I think that's called the nasal spine? Anyway, you can literally mimic the effect of bringing the nasal spine forward by putting chewing gum in your upper lip. Makes a big difference for some people depending on their area of deficiency.