Please HELP! Is this a seroma? 11 weeks post TT (photos)

Hi, MommyLof3.  I am sorry to hear that you are having problems after your tummy tuck and that you are concerned regarding the results.
A seroma is very difficult to see on photographs and is usually diagnosed by physical exam.  Typically, a fluid wave will be palpable and/or visible when the seroma cavity is pressed.  I try to distinguish for my patients the normal "trampoline" bounce or jiggle of normal skin as the swelling goes down, as opposed to a "water bed" wave.  Sometimes a seroma cavity can partially heal, leaving some fluid in tunnels.  This can be much more difficult to diagnose.  Also a small residual seroma may be such a thin layer that the characteristic wave is not present. 
The "pot belly" you describe may be due to many things.  If a seroma was the source, it would likely be a large seroma and obvious.  Some women are very slow to resolve their swelling -- I have found thinner patients, in particular, to have this issue.  Some women bloat on the inside and are slow to resolve.  Constipation will also swell the abdomen. Patient's who carry are considerable amount of intra-abdominal fat will have a more persistently protuberant belly.  If the muscles were not plicated, the belly will also protrude and have a pot belly appearance.
I find a correctly-fitting compression garment, avoidance of prolonged sitting and compression on the groin/lymph node area, avoidance of salt and simple sugars, a nutritious diet and massage help.
I would encourage you to follow-up with your surgeon for another evaluation.  An ultrasound or a CT scan with contrast can rule out missed fluid.  
Best of luck!

Call your surgeon and go back for evaluation.  Photos are poor substitute for in person exam. If it indeed is a seroma it will need to be aspirated.