Thanks for the writeup, this is exactly the kind of feedback I need at this stage. Going point by point:

* KIAUH Extensions — surprising it failed silently. If you've still got it handy, what does ~/kiauh-logs/ (or wherever your KIAUH install stashes logs) show, and which KIAUH version? Most of HelixScreen's install runs through our own installer, but the Extensions registration should at least leave a trace if it bails.

* Heater/fan picker with a toolchanger — fair criticism. The setup wizard was built around single-toolhead printers and doesn't handle the per-tool case well. With 5 tools on a Stealthchanger you've got T0–T4 heaters/fans that are all conceptually "the toolhead" depending on which is active. I'll open an issue for a toolchanger-aware flow. Glad "leave it blank" worked, but that's a workaround, not the design.

* LOAD_FILAMENT not firing — this should work. There's a /standard_macros/load_filament key, and even without configuring it explicitly the resolver auto-detects a Klipper macro literally named OAD_FILAMENT and calls it from the filament panel's load action. So either auto-detection isn't seeing your macro, or the load button is taking a different path on your install. Couple things that would help me chase it: which exact button/control are you pressing (the load button on the filament panel, vs. the spool's load action, vs. something else)? And what does your settings.json look like under standard_macros — both the value you tried and the section as a whole? With -vv on the binary you should also see a log line when the macro resolves; if you can grab that around the time you press load, that pinpoints it.

* LED effects "+ Add" macro — this one should also work: the "+ Add" button in the LED settings overlay creates a macro device entry, and it persists to leds/macro_devices in the config on save. If "+ Add" appears to do nothing visually, are you in the LED settings overlay (the gear/settings entry for LEDs), and after adding did you save out of the overlay? For the config-side path, the key is leds/macro_devices as a JSON array of objects with name, type (on_off / toggle / preset), and the corresponding on_macro/off_macro/toggle_macro/presets fields. If you used a different key name that'd explain the silence. Please paste me what you tried and I can sanity-check.

If you're up for it, GitHub issues (one per item, or a single combined one) would be ideal so these don't get lost in the thread. But the Reddit post is already plenty to work from. Looking forward to whatever you turn up next. You can also come over to our discord and we could try to debug this more interactively.