I can't guarantee these codes are correct but this is what I found out.
Re-entry codes:
RE-1A - Ineligible to reenlist, but condition waived
RE-1J - Eligible to reenlist but elected to separate
RE-1K - Career airmen
RE-1M - Eligible to reenlist
RE-1P- Eligible to reenlist
RE-1Q- Eligible to reenlist
RE-1R- 1st term airmen selected for reenlistment
RE-1T- Eligible to reenlist ANG and WSAFR airmen serving involuntary or involuntary EAD
RE-12- recommended for reenlistment
RE-13- recommended for reenlistment
RE-14- recommended for reenlistment
RE-2A- HQ AFPC denied reenlistment oppo for quality reasons
RE-2B- Discharged under General or other-than-honorable conditions
RE-2C- Involuntary separation with Honorable disch
RE-2D- Returned POW w/less 6 months active duty
RE-2E- Serving a period of probation and rehab
RE-2F- Undergoing, or separated while undergoing rehab in a DoD regional confinement fac'y
RE-2G- Participating in Substance Abuse Reorientation and Treatment prog for drugs, or has failed to complete reorientation.
RE-2H- Participating in Substance Abuse Reorientation and Treatment prog for alcohol, or has failed to complete reorien
RE-2I- Non U.S. citizen serving on initial enlistment
RE-2J- Under investigation by mili or civ auth which may result in discharge or court-martial
RE-2K- Formally notified of involuntary separation
RE-2L- Civil court charges pending for offense the MCM authorizes confinement; or court martial charges preferred; or court martial conviction under appellate review
RE-2M- Serving sentence or suspended CM sentence; or separated while serving or suspended CM sentence
RE-2N- Religiouus conscientious objector preclude unrestricted assignment
RE-2P- AWOL; deserter dropped from rolls
RE-2Q- Medically retired or discharged
RE-2R- Airman within 23 months of 55th birthday; completed at least 18 years
RE-2S- Airman within 23 months of 55th birthday; completed at least 18 years
RE-2T- Possesses HYT date of at least 20 years; within 23 months of HYT date
RE-2U- HYT date of at least 20 years
RE-2V- Applied for retirement, or retirement approved
RE-2W- Retired and recalled to active duty
RE-2X- 1st term, 2nd term or career airman considered but not selected for reenlistment
RE-3A- 1st airman separating before 36 months; or 1st term, no prior svc; females learning of pregnancy prior to enlistment
RE-3B- 1st or 2nd term or career airman ineligible to reenlist, ineligibility condition no longer exists
RE-3C- 1st term airman not yet considered under SRP
RE-3D- 2nd term airman who refused to get PCS or TDY retainability
RE-3E- 2nd term or career airman who refused to get retainability for training or retraining or delined to attend PME
RE-3I- Airman selected for reenlistment, by HQ AFPC removed the airman's name from the CJR waiting list within 5 months of DOS
RE-3K- Reserved for use by HQ AFPC or AFB for Correction of Mili Rcds when no other reenlistment eligibility code applies
RE-3S- Separated w/Special Sep Benefit
RE-3V- Separated w/Vol Sep Incentive
RE-4A- Hardship or dependency disch
RE-4B- Exceeding body fat standards disch
RE-4C- Concealment of juvenile rcds; or minority, or faliure to meet phys standards; or failure to obtain 9.0 reading grade
RE-4D- Snr airman or Sgt w at least 9 yrs TAFMS but fewer than 16 yrs
RE-4E- A1C or below completed 31 or more months; 1st term airman; or A1C or below w
RE-4F- 5 or more days lost time. Waiver req for reenlistment
RE-4G- No AFSC skill level commensurate w/grade
RE-4H- Serving suspended punishment to Art 15
RE-4I- Serving on Control Roster
RE-4J- Entered in Phase I AF Weight Prog; or airman ineligible for period of phase II
RE-4K- Medically disqualified for continued svc; or pending evaluation by MEB/PEB
RE-4L- Separated commissioning prog
RE-4M- Breach of enlistment/reenlistment agreement
RE-4N- Convicted by civil auth
RE-4- RE-3/93 recommended for reenlistment
Seperation codes can be found here, there are too many to list.
Seperation Codes