Understood and understandable. Compliments on adhering to a budget (sometimes a challenge with audio) and setting an example for your son.
You are likely aware that the Pendant is undergoing a not insignificant upgrade, Pendant OG to Pendant SE. Pendant (OG and SE) leans more neutral and has preamp outputs. Mogwai OG has more tonal weight, more power and versatility, and is solid state rectified; it also has speaker outputs. I have not compared these, but lower output may result in lower noise floor, especially for high sensitivity headphones.
If you don’t need preamp or speaker outputs, I would add the DNA Starlett for consideration, which is in the same range. It achieves gain variability via a switch (as opposed to tubes). For the DNA Stratus, the 6N1P and 6N6P input tubes can be swapped for 5dB less gain; I don’t recall if the same applies when swapping the 6CG7/6FQ7 and 6N6P input tubes for the Starlett. The Starlett (and Mogwai SE) allow for variability in power output and sag factor by changing the rectifier tubes: they take both 5U4G (more sag, less power) and 5AR4 (less sag, more power) rectifier tubes. The Mogwai SE can also take a solid state rectifier; I’m not certain about the Starlett and Pendant.
Your decision might be informed (in part) by whether you prefer more or less sag (i.e., whether you need tube rectification). When I was comparing tube amps in this category, tube rectification was a prerequisite. Good luck - these are all quality hand-built amps that one can enjoy for years.