You have 6 people that have no clue on how to turn on, home the machine, set offsets, load programs, dry run those programs and proof those programs in a machine.
You are self taught, but have you ever used the control type of machine you are buying? If so could you train them to properly use the machine and it's features when it hits the floor?
$25K is a lot of money, but if it means being able to successfully start the CNC side of the shop would that make it worth it? More so if the alternative is everyone is trying to figure out how to do this that or the other with the likelyhood of crashing the machines and requiring expensive repairs.
If the amount is affordable to your business then I doubt you'd regret it. I'd of course ask, which I assume you have, exactly what the training consists of, areas of coverage, how in depth will that coverage be etc. Also consider the training is an over view of the machine, it's features and operation, not a "How to be a CNC machinist" course. That leads me to an alternative.
One other option I'd seriously consider would be to hire an experienced operator/setup machinist that is familiar with that control and "proper care and feeding" of a CNC machine and use the 25K to pay his wages while getting the CNC side of your shop up, running and showing a profit, plus you have then created a job and hopefully brought a new level of experience and professionalism to your shop which could benefit the whole business. I don't know if the Japanese gov't offers incentives for creating jobs or not, so you may get a benefit there too. An experienced person could set an example for your "VERY YOUNG" guys not to mention bring the one thing you are missing that could very well make a difference in your long term success, experience.