I saw one other thread about this topic, but nobody answered it directly. What I want to know is, if you add an accessory to a lower * piece of equipment, then upgraded it to 5*, would the accessories get destroyed? I'm hesitant to use any accessories on my 4* gunner set because of this.
No idea as I've only added accessories to pieces that cannot be upgraded. It should keep the accessory intact, that would be logical at least.
One issue to watch for is that some lines don't support accessories in the same places. The Solid Cobalt Helm can attach accessories to the back but Mighty Cobalt cannot. There are similar issues in the 5* Miracle Helms too.