Allow us to edit what we've originally written in the thread, while storing an older copy in case of harassment / abuse in the original version.

Allow us to put a tag such as [ne] (No effect) over one of the bbcode tags to stop it from taking effect and instead be visible on the thread itself.
[b]Basicly:[/b]
Allow us to use [ne] to put red tags (for example) on our thread without it making a specific word red and not showing after we post. Will help new users understand existing tutorials.

If someone opens a thread / reply and links an item, embed the item onto the thread so the image + name of it appears while still being clickable.

Great idea!