Is the iPad mini 2 capable of running the DJI app without any issues. I want to get one (refurb) as my dedicated device to pair with my RC.

No, i don’t think that iPad mini 2 can run the latest 4.3.0 because people with iPad mini 4 are reporting issues,so just imagine iPad mini 2.
I have iPad air2 and it can barely run the latest app version well!

Safe Flying.
Alex.

Capable of running but quite a lot of issues.

Yes, it is very capable. I also use the Mini 2 as the dedicated device for my Spark and never had any big issues. Only issue I ever had with this setup was the video/photo buttons not always responding.
Together with OTG the app performs good and video is very responsive. I installed the 4.3.0 this morning and did a short test fligh, also no issues.