[yutt]

Since no one seems to be able to answer my question, I’ll post what I’ve discovered on my own, in case it could help someone who stumbles across this topic.

Digging through “..bb-includesfunctions.bb-template.php” there seem to only be a few hooks available in this area.

Post Form:

pre_post_form, post_form, post_post_form

Edit Form:

pre_edit_form, edit_form, post_edit_form

Some themes appear to have their own hooks. In kakumei I found:

post_form_pre_post, edit_form_pre_post

Unfortunately there doesn’t seem to be too much room to insert into the form in a theme-agnostic way. In-order to have things look right, you’ll probably have to modify the theme.