You took the long way round to calculate the current requirement. You could have simply added up the currents that you had noted on each module: 1 + 0.01 + 1 + 0.01 + 1 + 0.01 + 1 + 0.01 = 4.04
As for power supplies - please do not go for an LED driver. I would generally steer clear of any supply designed for low voltage lighting for this application, so option B is not on my preferred list.
The external plug pack - option A - has appeal for modularity. One capable of the current you require will likely be a switch mode design. A linear supply would be a solid brick (and harder to find). An external switch mode power supply (SMPS) would keep the mains and the switching circuitry away from your amplifiers - which gives you an added safety factor and will help with reducing switching noise. Also, it's easy to replace and by having a socket on the amplifier unit, allows alternate power supply options, such as a 12v battery, to be easily utilised.
The internal power unit - option C - is a compact solution, but this is also a switchmode design. You now have mains inside your box, so you have to be careful with that - and you also have the switching circuitry there as well. This might need some attention if the switching noise comes through your audio.
I should add - there is also the issue of how well these SMPS units have been designed, particularly with the separation between the mains and low voltage sections. If this is inadequate, there is an increased safety risk. However, the only way to check this is to open them up and look - presuming you know what to look for.
Then there is option D. Build your own power supply. The easiest will be to find a suitable transformer, add a bridge rectifier and some capacitors for filtering. This will give you a linear supply, where your only possible issue will be 50/60Hz hum - but that's something that has been dealt with for a very long time.
However, there is one thing that I am curious about - and that is: What application are you going to be using this unit for? It seems a bit strange to have four microphones and four power amplifiers running off the one supply. I'm not saying it can't be done - it most certainly can - I'm just wondering why.