The question is do you have the time and post processing facilities to edit the C200 RAW into a deliverable format? The C300II has more codecs for easier editing and / or better quality straight to broadcast delivery.
I agree and also should consider if your shooting raw lite, both the 200 and 300 have short runtimes, around 15 minutes a standard cfast2.0 card.
If you don't have a sound tech on set, then the 300 offers a little bit better sound recording than the 200.
If your renting, I suggest an extra two day rental minimum to get familiar with either cameras controls, prior to shoot, and always give the talent a sip of water between takes. It calms them and eliminates scratchy voice.
This is your project so you will know the script, though many clients have a script that is not in the way each person talks. It's important to let them read and rehearse before hand in their own voice and make small changes to fit their personality. After shooting if time permits keep them in the same spot of the scene and do a v/o if you plan to do cutaways. Same with adding some foley sound.
A soundtrack behind the interview will cure a lot of ills as long as it doesn't get in the way. We have a sound mixer/tech that can work wonders matching clips and blending the sound and he is inexpensive for short form. PM me if you want his information.
All the best,
BC