I know theres a lot of production behibd the drum sound on "Brain in a bottle" and "the mother lode", but whats the closest you could get using an ipad? Any specific drum machine app perhaps?

I’m sure you get get very close to basically any standard (kit or machine) drum sound with the Fingerlab DM1. If for some reason doesn’t make you happy, get the iMPC (or other sampling drum machine) and start sampling.