matsonfamily

The FD lenses are versatile, but if you go EF you can adapt most DSLR mounts other than FD or MD to EF with cheap & small adapters that can be left on the lens.

If you're using an FD to X adapter, you can only mount FD lenses or M42 as well (if you can find the rare Canon M42 Adapter).

Note if you are adapting only manual lenses, a non-electronic EF adapter can be used readily, which are cheaply available but don't support controlling native EF lenses.

Given that Irident is free to try, why don't you see for yourself?
 
The "painterly" effect comes up mostly with foliage and very fine detail. Personally I am reasonably happy with Lightroom most of the time for relatively small prints (at least up to A3+).
 
But for A1 and maybe even A2 Irident (especially disabling noise reduction and distortion correction) and the free/donation-ware RawTherapee* both extract IMHO a huge amount of fine detail more than Lightroom, even using in LR the Bridgwood sharpening method(s):
 
SHARPENING X-TRANS FILES IN ADOBE LIGHTROOM
 
*In RawTherapee for the best results you'll have to use "Deconvolution Sharpening" and "Microcontrast" sharpening at the same time

Hello and welcome. After having tried several, I ended up using RawTherapee (I'm on Linux).

You have to change it for every lens you mount on the camera.  That is why I wish Fuji would allow that setting to be added to the Q Menu !!!!!
 
The value you enter does nothing to correct the image due to any possible lens distortion.  It is only adding that focal length to the EXIF data.
 
Have fun shooting with vintage adapted lenses. 

For fear of stating the obvious, is it *definitely* not turning on? I had a similar situation where I thought it wasn't turning on, but I had just inadvertently pressed the 'view mode' button (to the right of the EVF) with the effect of switching off the LCD; since then I keep it mainly in 'EVF only + eye sensor' mode. Again apologies if this is an exercise in teaching granny how to suck eggs, but sometimes the obvious can be overlooked.  

pixel shift would be nice to be able to get higher resolution files but from what i've read the x-trans pixel pattern makes it harder to achieve this compared to the bayer arrangement...
the GFX100 i think does have pixel shift but i'm not sure whether it's bayer or x-trans