Would absolutely second the quicksilver suggestion if you can find one, awesome amp for the money, check out the thread for more info
Should work with really all your headphones except the he6 and lcdx could be hit or miss. Only concern would be that it might be a bit heavy, but shouldn’t be too bad.
The WA6 is also pretty solid and should give you good flexibility, I do prefer the quicksilver but the woo is going to be easier to find used and will be smaller
While it would limit the headphones you would want to use, the Feliks echo isn’t a bad pick, and would be lighter than let’s say the quicksilver, have a comparison to the QS in the aforementioned thread
No balanced inputs for any of these, but the problem you’ll find is that there’s a pretty significant price jump for something with balanced in (transformer cost), and it also will add weight and size. The BF2 has about similarly good single ended outs that you can use at the same time as balanced, so you really wouldn’t need a switch. Though that would be skipping the lokius, if you wanted that in the chain I’m not sure how it’s single ended outputs are (but honestly I wouldn’t put it in line with something like a QS since imo I think it would cause more harm than good sound wise)