Whoops, found a small bug.
In the template
diary_editdiary_addowner, change the following line:
Code:
<div class="smallfont"><a href="$vboptions[bburl]memberlist.php?do=search">Find Member</a></div>
to this (note the /):
Code:
<div class="smallfont"><a href="$vboptions[bburl]/memberlist.php?do=search">Find Member</a></div>
The zip has been updated with this fix

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And once I install a test 3.5 forum and familiar myself with the structural differences, I will try and write this for that, too

.