I can only go by what the block numbers are on the open data source I've access to.
the 17:35 service 9 comes off the 17:17 arriving 9 and then doesn't do anything else.
The new early morning 44 does the 26 from Levenhall Roundabout, sorry omitted that.
May be unrealistically high but its what the block numbers show in the open data.
The 14 has had buses swapping already at weekends (early mornings)
Checking Lothian buses website for future dates (not the press release pdfs), 05:52 8 from ERI terminates short at Pennywell cottages (similar to what the short 8 from Leith St does) This is also the case for the 10:13 and 2055 service 9s from Kings Buildings.
Checking Lothian buses website again, you will see that the 10:30 and 11am service 24s to ERI do not stop at Stop IA like the full service 24 does - this also happens for the 12:45, 14:00, 17:18, 18:06, 19:17 run. The same is true of the 7 timetable due to the interworkings.
The evening 36 has a longstone block number hence my belief it will be longstone run. The 27 that works onto the 25/X26 has a marine block number so likely as you say is done by the shuttle bus.
Likewise the X40 has 5 blocks (4 during the day showing recovery time at livingston end.)
The 1629 appears to be fresh out of the garage and works 9's until 10pm then two 14s.