Still slogging away, but getting much closer to the end game on this...
In case it wasn't clear where I was going with this from my earlier pics....
Here's the legs finally installed and cut to length. The printed brace is secured with 5X 2" wood screws through 2 pieces of 1/2" plywood and finally into the 2X3 framing on the top (bottom in these pics) cabinet + 1 machine screw through 2X plywood where the brace hole didn't line up with the 2X3 frame, 2 smaller wood screws to the side of the pedestal (top in these pics), and then the wood + brace are secured with 3 carriage bolts through the pedestal's 1X3 side and then just the brace + wood secured by carriage bolts (I've since grabbed some shorter ones for the wood + brace holes). Once everything is stained and in place, there's also a spot for 1 wood screw on either side of the brace to secure fore/aft (they're offset from each other with the thinking that'll provide a wider link between the wood and the printed base).
Very happy with how the carriage bolts turned out. I had initially been going to grab just some standard hex head bolts, but saw these in the hardware bins and thought they'd work out better. I've got large(ish) washers + lock washers + nuts to secure them with and then am going to cap the ends with some printed thread caps.
Legs have been measured / cut to the correct height, and this front cabinet is solid as a rock! Legs have been removed and are currently undergoing stain (HD still has a few cans of $12 stain marked down to $3.50 so I even managed to get the same colour/stain...
).
Plastic trim shown isn't installed yet, but was finally checked for proper fit and seems to be fine. Still need to print off some button plates for the front as well as drill out the button holes and start wiring (which unfortunately is going to include more splicing...
).