Hello there wonderful person! Kiwi here (the main developer of the game), firstly, I do apologize for the long wait for a response! Secondly, I'm so happy to hear you're enjoying the game.
A) Thank you for asking, as this has pointed out that I never quite explained what Faults were! ...And to be honest, it has been so long, I'm not quite sure what I was going for with it, as you already get different placings for missing specific rolls. Most likely, I was laying down the groundwork for Show Jumping - which does have a certain tolerance for faults i.e. hitting the jumps, but that is something for the module/expansion. Honestly? Ignoring it is precisely what I would do in your situation. I will be adding a note to my development trello to remove mentions of it in the next update.
B) This is a very fair point! I chose Barrel Racing precisely because they are so simplistic. While I'm pretty sure the Show Jumping Module (the current expansion I'm developing) will be too complex to include in a base game, I do think that Flat Racing / Steeplechases would be an excellent compromise, as they would test Speed and Stamina first and foremost. (The other stats have other tests, promise!) I appreciate the kind words, but I also appreciate the input!
C) I still am, yes! Life sure is crazy, and with everything going on in.... everywhere, right now, as a solo developer (who has no financial incentive to develop this passion project), it has been taken by the wayside. It /is/ good to know what you're interested in though! I've toyed around with a resource management side (such as having to buy land, feed your horses, etc.) for more money sinks, and I DO want to eventually bring about a genetics module for breeding. (The main reason I'm putting emphasis on modules is so people can pick and choose how they play.)
D) If you made homebrew content I would cry actual real tears. That is to say, I wholeheartedly approve and would be touched! Obviously a linkback to the base game is welcome, but as far as I'm concerned the game is open to be added to and you should always modify your games to make them more enjoyable for you.