I don’t see the need for LP205 or LP206 as these would need to become ‘pre-set’ shunt signals within the main aspect routes and also when 103 could have a LOS up the branch replacing 206 and then the subsequent opposite direction would utilise 112 replacing 205.
In regards to your final question, if you had also designed in track circuits on your scheme plan, LP103 & 105 would have in place TER (timed electrical release) where their berth track circuits were occupied for say 30 seconds on their own with the tc of that berth in rear having been cleared for that time also to ‘demonstrate/prove’ that the train had been ‘electrically’ timed to a stand. Another way that we do this, is that if we set a route from 101 to either 103 or 105 and the route from 103 or 105 is not already ‘pre-selected’, 101 signal becomes approach controlled from ‘red’ thus as belt and braces making the approaching train being at a speed of which the driver is prepared/ready to stop. This is a compromise in absolute approach locking as we nether have flank protection applied by existing S&C or by run offs. Once this down direction train was ‘electrically’ proved to a stop and UP direction service could be signalled off the branch.
Another way it could be done is that if first a train is signalled from 112 in the UP direction, the interlocking would have a ‘special control’ where if 112 was showing a proceed or had an overlap going past it, a proceed aspect could not be obtained on 101.
hope this helps