Always funny how people on a budget make decisions guaranteed to get the least out of scarce funds. I don't know how it works with guitar amps, but with audio every wire and connection matters. In general the more complicated you make something the harder you have to work to overcome your complications. Like even going separate vs integrated adds a power cord and interconnect. All this stuff sounds better on springs so add a set of those. Fuse, ditto. You just upped your cost profile hugely merely by going separates instead of integrated.
You want to bi-amp? Now in addition to the extra amps you need even more power cords, interconnects, springs and speaker cables. Plus oh yeah now you need a crossover. With power cord, interconnect, etc etc etc. Multiply times three or four.
You really want to have a great system to enjoy for years and years? Don't try and reinvent the wheel. There's good reasons hardly anyone does what you are talking about doing.
You want to bi-amp? Now in addition to the extra amps you need even more power cords, interconnects, springs and speaker cables. Plus oh yeah now you need a crossover. With power cord, interconnect, etc etc etc. Multiply times three or four.
You really want to have a great system to enjoy for years and years? Don't try and reinvent the wheel. There's good reasons hardly anyone does what you are talking about doing.