Your selling dealer sounds lackadaisical. He should not have some kid assembling crucial parts of the backhoe without serious supervision. Drain Plugs and similar don't come loose from vibration unless improperly torqued to begin with. ALL grease zerks should have been hit with grease before delivery, though this often gets overlooked. Greasing of the hoe is crucial to it not wearing out. Key items like pivot pins do not wear well without grease. Same goes for the entire tractor's zerks.
Hydraulic leaks are not acceptable and can be dangerous. NEVER search out a leak with your bare hand, ONLY use a wood block! Hydraulic fluid under pressure can penetrate skin, causing serious problems, including possible need for amputation, depending on severity. Best practic: locate general area of leak, shut tractor off and remove pressure on the lines by moving the joystick through all its positions; then look for where the leak is originating.
PTO fitment issues are not uncommon when one's tractor is capable of fitting different categories of implements. At the very least, the dealer ought to make sure what you have, (mower) will mate with the PTO shaft provided, and that if you need any bushings, etc. that they give/sell them to you with the implement/tractor sale(s).
What brand of battery is in the tractor? There is on the side of each battery a date code stamped into the case, usually near the top edge. This will determine when it was manufactured. It's possible, since it seems your tractor was most likely a new on the lot, but used for demo purposes unit, that the battery has gone through numerous cycles from charged to partially or completely discharged state. If so, the life is likely shortened by a good amount. If it were me I'd ask for a brand new, fresh stock, new battery.
What's your serial # on the tractor? I ask because this is what determines year of manufacturer of the unit. Tractors are sold with their warranty beginning the day of sale/delivery and don't necessarily coincide with the year of manufacture, since they often sit on dealer's lots for some time before retail sale.
I very much doubt an employee was going to buy your tractor, then decided to buy a smaller one. That smells of dealer salesman BS/hype, IMHO.
How many hours were on the meter when you took delivery? They broke it in for you?!:confused2: What is that all about?
BTW, you have a great machine. Kioti tractors are excellent workhorses, in your case, after all the initial bugs, caused by the dealer are worked out. Try not to obsess about it; just get things looked after and let the dealer know that you expect better results in his dealing with you going forward.
And for all of our ease of reading, use some paragraph breaks. It makes following your story much easier to comprehend.
Good luck; post back results and any further questions.:thumbsup: