Thank you for your support! It means a lot that you really enjoy Homecoming. For the moment, Ten only has the one sprite, and Shun hasn't received his new sprite rework yet, but please do look forward to it. We're likely going to be making him look similar to his original style, but aged up a bit (so he doesn't look like he's 8 years old).
Homecoming uses the Ren'Py engine, which is constantly being updated by its creator to include new features. It can be a bit daunting to use at times, because it requires a little bit of coding knowledge. As a matter of fact, some of the features within (like the credits sequence for example) were a result of some trial and error. We are planning on adding more to it later down the line, but there's no timeframe for it yet.
Lastly, I'm glad that you, like so many others, really like the Ten "route" and want it brought back. Especially since I'm the one who wrote it. It was never meant to be anything official, and more of a way to show how custom routes could be done. I wrote it after having read the doujinshi My Summer Vacation With the Captain, when I realised that Ten was my favourite supporting character. While we don't really currently have plans to add it to Homecoming, especially since of the amount of work we put into each day/character, many elements from his route will be making their way into Juuichi's route. If we were to bring Ten's route back, it would require extensive reworks to bring it up to the standards we have set for Homecoming, which would take time away from the more key components we're working on.