What route should I pursue, 88N, MP, CID or dog handler?

You have almost no chance of getting a class seat for dog handler. 88N is a good job, but if you're looking to pursue a career in LE then CID is exactly what you're looking for. You don't need to finish your degree before you apply, you only need. 60 SHs.

MP. You might want to pass over dog handler because they are required to approach suspicious vehicles in combat zones, typically car bombs, If you have a family awaiting your safe return it's not ideal. MP means going to Missouri for MP training. You'll qualify on many weapons and can be placed anywhere in the US, including Hawaii and Alaska. You'll mainly be patrolling family housing areas and gates. Excellent experience for transferring to civi police. I grew up on base and the MPs spent time largely with bar fights, domestic violence, AWOL investigations and there was MPs all around the playground where the kids played (to make sure they wore helmets when riding their bike, etc. ) it looked fun but I wasn't OK with patrolling Baghdad so I did something more in my comfort zone.

Good evening Sir......... all the jobs you listed are beneficial in the civilian world.. But whichever job you decide to do, you will be fine........