Kafi - you are correct. The only way to give someone the ability to edit comments left by others is via hacking or via making them a moderator.
Bacon - Thats a bbcode relic that occurs via the auto synopsis function. What you CAN do to work around it is edit the functions_geekarticles.php file and look for the first function (think its called prep_for_broken_tags). In that function you will find an array of codes liek [url and such. What you need to do is enter a new one for [size= and it will get rid of it. Sorry I cant be of more help... Im still on Holiday

BTW: the next version will have an admincp page for this.
Sketch42: It just follows the same flow as the new Thread button. However I am sure with a template mod this can easily be done... However I couldnt tell you off hand as I dont have any of the code with me.
Musicman - Tough to say... looks to me like you have missed uploading some files. Is it when creating a new article or when uploading an image header? I would download the package and reupload the files.
Fribs. Basically - yes. However this really depends on what you are adding and what it is for. In function_geekarticles are the fetching,inserting and updating functions so tecnically you only need to add more fields, change the sql in those functions accordingly and then your editpost and newthread fields to pass and catch the fields. However I couldnt really give you too much of a hand with this as I previously mentioned Im away on vacation. I couldnt think it would take you more than a few hours tops depending on your level of expertise.
HTH?s