My cylinders are all 16" of travel. IIRC, that is the same as or very similar to Kubota's B219. That is not to say you cannot make shorter cylinders work, but the shorter the cylinder, the more leverage that must be applied to get the same travel and the harder it is to be smooth in operation.
To illustrate by extreme thought experiment, 4" long rams used as a lift cylinders would have to be placed very near the pivot point between the lift arms and the support towers instead of supporting the arms midway, near the bend. So the towers and arms would have to be made of much heavier, stronger material to lift the same load. The cylinders would have to be much fatter diameter to apply the necessary force. So much so, that I doubt there is physically enough room to mount such a fat cylinder.
Placement of the cylinders is crucial. The angle has a huge impact on the actual lifting force that is applied. For example, a 2" bore cylinder fed with 1700 psi, mounted at 10° from horizontal will exert a vertical lifting force of 927lbs per cylinder at the fulcrum point (ie: the attachment point on the arms). But mounted at a 5° angle, the vertical force drops to 465lbs per cylinder. At 15°, the vertical force leaps to 1382lbs.
If the attachment point is exactly 1/2 way along the arm, then the true lifting force "at the pin" (attachment point of the bucket) is 1/2 the force at the fulcrum. Of course, the lifting force at the cutting edge (lip) of the bucket is notably less and also the lifting force has to lift the weight of the FEL components as well as the material in the bucket.
I found an on-line hydraulics angle calculator
like this one to be invaluable during the design phase.
Ideally, you want the lowest point of travel for a flat bucket to be between 1" and 3" below grade (You can't dig unless the bucket can be lower than the wheels!). The highest point of travel should leave the lip of the bucket in the fully dumped position forward of the front of the tractor (you don't want to dump the load on your own hood!). I set mine up so the lip of the fully raised and dumped bucket is a few inches forward of the back of the bucket when flat on the ground.
The leverage effect also means the maximum height of the arms is extremely sensitive to the mounting point of the cylinder ends on the support columns. An inch difference in mounting height on the columns might mean a foot difference in lift height at the bucket.
In summary then: Yes, you can probably make 14-1/2" cylinders work if
you carefully account for all the variables and can accept the resulting compromises. I have focused on the lifting arms in all of the above, but similar considerations come into play with the curl cylinders. That said, it is my gut feeling that one would require fewer compromises using shorter curl cylinders than required to use shorter lift cylinders because the lever lengths are much shorter in the curl geometry.