At the bottom of the first post of the thread that you linked, it states that your method of waiting for the ancestry of the character to change is broken and that you have to check for the parent first. It even provides code for the fix.
This is a different (and unrelated) circumstance. Characters do not have their appearance automatically loaded and replaced via HumanoidDescriptions. Automatic appearance loading is disabled and substituted for starter character assets. Armour pieces and weapons are attached to the character via accessories.