Useful information to put in your algorithm:
When branch assignments are given to commissioning lieutenants, OCS gets the last pick. USMA gets first pick of the available allocations. The 6 senior military colleges get 2nd pick. The rest of the 270 ROTC programs get next pick. OCS gets whatever allocations are left over.
What does that mean to your friend? Last year the Army commissioned 6195 new 2LTs (from all commissioning sources). Of those, about 250 were assigned to the military intelligence branch (because the Army honestly doesn't need very many MI officers). Only one allocation was not filled by USMA and ROTC - that's right, only one allocation for MI was available to all OCS commissions.
As the Army contracts and changes the BCT shape, the number of LTs will obviously decline as well. Next year, with an end strength of 490,000, the appropriation is for about 5800 2LTs. FY17's 420,000 end strength is expected to need about 4900 LTs. The USMA and ROTC classes are already locked in for those FYs, so where do you think the cuts to commissioning rates will come from? That's right, OCS. And, as the BCT shuffle completes, the number of MI LTs will decrease.
What all of this means is that if your girlfriend wants to be an intel dork, there is an infinitesimally small chance she will get that by going through OCS, especially if she does not have prior enlisted experience as an intel analyst (with a TS/SCI clearance done).
Her two realistic options are to take the 2-year ROTC scholarship or pursue an Army Reserve direct commission (extremely small chance with no gov't intel background). There are 2-year ROTC scholarships for grad students. If she has not completed basic training and AIT she will be required to go to the cadet basic summer camp at Fort Knox before signing her contract. It's a 3-week "this is what the Army smells like" camp for late ROTC joiners that's stupid easy.