Having more than one USB 0404 certainly changes the risk assessment - I keep looking but no luck on that aspect for me.
Unfortunately capacitance and maybe ESR can change the design performance of a dc/dc switchmode. ESR changes a lot with temp, so to have a substantial change in stability due to say a 10:1 change in ESR seems a bit concerning. It would get arduous to assess why there was a high level stability or control change when a cap is changed, but at least you can swap it back or change it again to do some basic fact finding.
(I am trying to identify the purpose of two of the electrolytics. My "new-old" E-MU 0404 DAC THD improved by 2 dB on the worse channel with new capacitors. It still is a couple dB worse than my "old-old" E-MU 0404 which still has the original capacitors. The "new-old" one arrived looking pretty new physically. It might not have been used for maybe up to 10 years. The THD improve by a few dB just being powered on for a few hours and then a couple more dB when I put four new 47uF 63V Panasonic capacitors next to the DAC.)
Had a quick look at ARTA, it seems quite complex.I had a go at producing THD vs Freq., never done this before, is this what you're after?
I'd like to carry on with REW first, as I've started with it. If the same needs doing in ARTA, I think I would need some help with that.