A bit of a late reply perhaps but as for headphone amps I can recommend the Sonicake Pocket Master. I use it mostly for guitar and then only as a headphone amp and bluetooth/aux in device + IR loader.
It’s on my practice board together with a couple of affordaboard type pedals from Movall, Rowin and Mosky and I’m very happy with it. The Pocket Master has bass amps and presets (admittedly not many) but it’s versatile, sounds good enough to my ears and has a useful tuner and even a looper. It supports my M-Vave Chocolate MIDI controller for a more useful footswitch type control.