Would you want the monitors to be similar so you could mount them all together or would them being different and just being on normal stand ok?

I would say something similar to this, https://pcpartpicker.com/list/dbkb29 however your monitor choices is all up to you. Whether or not you want RGB, etc are all personal choices you would have to make. Liquid cooling, or fan. Could definitely save some money by changing out the CPU cooler for something else, cheaper RAM that doesn't have RGB, cheaper/less fancy looking case, and all that.

What I quickly put together has room for about another $200 into monitors but could easily be adjusted to be cheaper to leave more room for monitors.