FIR butterworth also possible or just IIR?
Filters according to those optimality criteria only exist as IIR filters. They are derived from the corresponding analog prototype filters via the bilinear transform, and this naturally results in IIR filters, i.e., filters with zeros and poles (away from the unit circle).

Of course, you can approximate these filters by FIR filters. The most straightforward way would be to truncate the infinite impulse response using some window function. But such an FIR filter is not optimal anymore since it can only approximate the optimal response.