It seems that you have already done your research.
Go for the beyer dt770 pro 250 ohm, or even better, the tygr 300r. Any of these two will fill your needs.
As for the dac amp, you can choose between schiit fulla (recommended), fiio k5pro and ifi zen dac, and many other good options.
Also, take a look at this post for a ton of useful information: