Analog PS3 (3 pins) thumbstick (or mini-stick) don't need amplifier.
The theoretical advantage of the PS3 HALL thumbstick is better signal stability and longevity, but don't know this worth the extra "complication".
But in any case is just matter of get Debolestis PCBs on OSHPark, are ready for use (errh solder).
For TQS - get one OSHPark Debolestis 2 chip Shift Register board, this is sufficient for TQS 10 buttons (counthing the mini-stick press). Fit this board inside TQS handle - measure the available space first do avoid "surprises".
I don't think that worth change TQS "gimbal", the actual work OK for the purpose, even for contactless sensor - that require a play less movement. Unless you plan use something like GVL-224/Dvik throttle "mechanics".
About Fl6 FLCS new gimbal, first measure the available space inside base base to see if any of this designs that you plan use fit there.
Desktop joystick cases general has little height what can complicate use one or other gimbal not designed specific for a given case.
Pay attention too if the new gimbal designs allow you easily fit the PCB for TLE501x - the most commons PCB measure ~40 x15mm. But in any case you can design and make a specific size PCB for TLE's.
Maybe will be interesting - facing the work and cost do make a gimbal - get one BAUR BRD-DS (desktop) gimbal with case for FLCS. They are "bullet proof".
I find the ones in that mentioned topic... "non innovative".
Or, Debolestis are working in a 3D printed (for use ball bearings) "clone" of UberNXT, what was the best alternative gimbal for Cougar in their "hey days":
