Looks like you have the multiple info in one forum box figured out, that looks great !
If we want the description to be taken from the wiki, we need to have a sub page that contains that data and because it is just simple text that can be a simple sub page I think Creature:Hackfin/description.
But to really make that data useful for other purposes we need to make that be accessible with a query. So basically make a property like Description (make it a generic one so we can use the same on for other descriptions) and put a text box in the Form:Creature to fill in the description.
I think something like this should get the description into a table, did not test it though, so it might need some tweaking.
{{#ask: [[Category:Creature]] [[Creature::{{FULLPAGENAME}}]]
| ?Description=Description
| format=table
| align=left
| headers=plain
}}
Anyway, need to get some sleep right now (1 am) but I will give it a go tomorrow and see if what I made up out of the top of my head actually works