The AC is not rectified, the contactors are AC and will not run off of DC. Low voltage 24VAC is used for the control system, power to the front panel and spindle switch that then activates the contactors. The 24VAC voltage will fluctuate based on the load, contactors closed will draw more current. I am assuming KA is the main power contactor, KM1 and KM2 are the motor run in the respective direction. Transformers do not give a fixed output, their unloaded voltage can be much higher than loaded, varies by design and also the VA of the transformer. As far as how long LED last, there is a big difference in the quality and the design of the LED's and also if there are multiple LEDs or just one. With multiple LEDs in one lamp, you often see a cascade effect, one fails and then the remainder draw more current, and then the next until they all burn out. Ironically when I buy say a Philips brand LED lamp, I have yet to have one fail, the cheaper brands, in particular the junk on eBay often fail much sooner. I have also seen similar issues with the incandescent indicator bulbs, I often will source NOS like GE and they function correctly. I have measured the current, the newer lamps draw more current and shine brighter, and do not last. Reason why I mentioned just going with a decent brand LED indicator light after all the headaches you have had.
The transformer looks like it is around 63VA so around 2.6A, but is fused for 1A (FU3).