Your idea of creating ramraj is good but in reality it is different. Very few labours want to upgrade themselves. Govts made them addicted to get free things. If you create jobs they think that you are getting rich. You need good amount of effort to brainwash them.
Now the situation in many places is this: creating job is not enough you have to plead them to take up the job. This may not be the case in all the places but situation is not different in many places.
There is no cheap alcohol available so they demand land lord to buy it for them. Take my case, past 4 months labors are not available(because it is ginger season). If I want I have to provide breakfast+Lunch and booze for them and pay 500rs/day. This costs around 620rs. I can get two engineers(of 1year experience) for this salary.
It is for you to decide how you want to handle the project, if you are PMO certified then don’t try to apply those gyan on dairy. It really don’t work.
You will face obstacles everyday and these obstacles make you adopt ad-hockery.
Ok now to your questions.
with 1 acre you can grow green fodder for 5-7 but barn and store also needs place so consider 4 animals can be accommodated in your case. If you are buying green fodder from other then it is a different issue. 10animal dairy gives you a decent income of aprox 25 to 30K.
Investment for 1 animal is aprox 1.5 lacs( this includes barn construction, milking machine and other basic accessories.)