A quick read of Q4 suggests the following might be possibilities.
|ContentTranslation||end of Q4|
|New PDF rendering||end of Q4|
|3D (on beta cluster)||end of Q4|
|Syntax highlighting in classic wiki text editor||end of Q4|
I would suggest cancelling the Bug-a-thon for 2018 and, considering the available technical manpower in November, aiming for the translate-a-thon to primarily be a volunteer event with us inviting and coordinating and possibly preparing some suggested focus areas. While staff who don't know how MediaWiki translation works could join to learn that is complicated by a volunteer event having to be organised outside of regular work hours.