Adding a farm draft to a league

[roadtrip68]

We are having discussions in one of my league to add a minor league draft. Up until now we could draft whoever we wanted to in the league draft and pick up whoever we wanted to via faab during the season. There are many different opinions of how this should/could be done. We can use some help and advice. My thinking is -

-if a team has a minor leaguer he can used as one of his keepers for this year only.

-only minor leaguers on the forty man roster at the time of our draft could be drafted in the regular draft otherwise he would fall under the new farm draft. (this one will be getting the most different opinions of how it should be dealt with)

-after the season starts a ML could only be gotten once he is brought up by his club.

[Grinch]

Suggestions:
***Allow freedom this year as players should not be penalized taking some one last year and then the rules changed. So you could keep as many minors as you have (up to whatever you set your max at)
***Do not allow any minor league players to be drafted in the regular draft. If you draft BEFORE opening day maybe a rule where the player must have appeared in the majors last year or be listed on a respected site as expected to be on the roster---MLBDepthcharts.com for example (in my keeper league we draft right after opening day for this reason).
***Make sure your rules on who can/cannot be drafted in the minors are clear, some problems can arise if not. For example, in 2004 before we made it that the player had to be ROY eligible, the first guy picked in the minors was Ugueth Urbina who had just signed to close for Det, but was not game ready yet. Other issues--if it's an only league can you pick players not in that leagues minors, Japanese players, retired players (Clemens caused different problem for us FAAB vs injury replacement).
*** Define the rules on trading minors (do you set a max number)
*** Define the rules on trading picks---how far ahead can you trade, next year, 2 years, etc.