The first couple monsters seem okay. Leone is Volcanic Rocket, fine; what does it search? Some archetypal S/T. (We find out later what a monster it is.) Venom, Giraffe, Jumper, okay whatever. Generator D is a repeatable Foolish Burial, but it doesn't seem too bad given you don't care much / benefit much about filling your Graveyard. That's fine too.
This is where the wild ride starts.
Generator Castle is a balanced card! It's singlehandedly better than Black Whirlwind, Madolche Ticket, and Wind-Up Factory combined. What a feat. And it's searchable by Leone. Wonderful. Plus you get a freebie 900 burn, but that's not the important part.
Byrdie is extremely awkward; its stats are very high for what it does (draw 2 pitch 1 when it's summoned? ok) with no restrictions whatsoever. Look at Cardcar D! What if you don't have a Thunder monster to pitch, do you just pitch your entire hand or it simply fizzles? Can you only activate it while you have a Thunder-type in hand? There are a lot of questions I can ask.
Cube of Genemal Summoning. Great, a Quick-Play version of Advanced Heraldry Art with no restrictions whatsoever. Just summon two from your Deck, no problem! And Heraldic Beasts are horrible for the most part; your monsters are actually playable. Chain this to MST! Summon two Venoms and make your opponent cry! You can do whatever you like. Instant Xyz. Quick-Play (I know I mentioned it once but I think I should do it again).
Foxxei's biggest problem is that it has no restrictions, but it's also just ... free cards when usually a cost should be paid. Surprisingly (but unfortunately), it's not even in the top three of the big problems.
Siehorse: So you have a level 4 shuffle-to-deck monster on any Summon. That also deals damage. Sure. I, uh, I would probably reconsider this one too. Or maybe scrap it altogether but it's probably actually salvageable.
Generator C: Free destruction all day every day! Kill your opponent's facedown Spells! Traps! Monsters! You name it! Do it every turn! Also free fodder. Not even Fire Fists play the game like this. C'mon man.
Xyz Golem: See this card is actually fine. A little underwhelming, I would even say, given that Cowboy exists. But ...
Dracosaurus: This card's effects would be ok if it had less ATK. As it is it beats for 2900 off a 2-material rank 4 body without much in the way of restriction. And your archetype is supposed to be burn!
CXyz: This isn't even necessary, guy. 3400 ATK is the main problem here once again. That and it can summon free monsters from your deck. They're both problems; see M-X-Saber Invoker for a somewhat balanced (but still very good) model. This card is outright overwhelming archetypally, especially because you can go Cube -> Golem -> burn -> CXyz -> more plays, or just use a spent Dracosaurus since, wow, you don't even need to detach to activate this card's effect.
Genemal Buster Pistol: Last card. Nontargeted 3-card destruction with no cost. Burns your opponent for 2700. Don't give me "oh but it costs LP to activate since it burns you too"; yes it does but you get 1500 of it back for free (???) and your deck is a burn deck! That means you're going to have your opponent at lower LP the majority of the time. Oh yeah and this is a Quick-Play too. I'm getting Fire Lake flashbacks, except this is doable anytime anywhere (scary thought).
Phew I'm done. I apologize for my tone, I just thought the set became progressively more amusing as the card number went on. Mi-steaks are always made while starting out, so don't sweat it.
Summary: I liked some of your ideas, especially the earlier couple monsters, but as it got further into the set it seems like you just slapped on whatever seemed strong and added some burn damage, then called it a day. Your monsters don't even have bad stats. A bunch of these cards are also generic and therefore format-warping. I recommend you define the archetype a bit better and both reduce and focus its strength.