I have corrected the loop signalling to rectify problem (2). Your signal rationale is clear, no sense re-making videos when there are doubtless better tasks to push forward. Whilst the videos are good, some of us learn/remember better by doing than listening, and videos are not text-searchable when you have a question. I'm sure we'll all pick it up soon enough!
I have then re-tested, and as you will see from Savegame J attached, the passenger train does not 'stick' any more at Halfway Loop entry points (so 1 is also solved)
However, incidental to this two more issues have arisen. The first (3) is probably a bug, but not a signalling one, so I can put it in a new thread if you prefer? The second (4) is a signalling matter, but may or may not be a bug...
3. See savegame revision J (and image 3). Eastbound freight should depart 3 minutes behind the eastbound passenger (according to schedule) but actually 5 minutes (held by signal at danger). However, at the designated time, it actually lurches forward several tiles, then begins reversing, for no reason I can see. It should reverse, if necessary, during its time in the station. However, as it came from the depot and is already facing the correct way, it shouldn't reverse at all. The additional reversing time throws the schedule out of synch.
4. Stop Signals in single track working, seem to actually adversely affect (or enhance!) block reservations if they occur after the Station Signals.
See the test game version h attached (and image 4) in which the east terminus has a Stop Signal after its pointwork when departing - because I forgot to delete it like the rest.
In this case, owing to that extra Stop Signal, the slow westbound freight reserves the middle block section right from its initial departure, long before it gets close to the Twothirds Loop. This means when the passenger train arrives at the block, it is reserved, when it should be free. If the Stop Signal is not present, it only reserves to the first loop.
Interestingly also, when that reservation is made, if I use the "b" tool to see the reservations, and manually clear the middle loop reservation, a single tile remains reserved by the westbound freight , unable to be cleared.