Power restrictions for Analog signals and overcoming them

So I am looking at a data logger and irrigation control.

I have answered and specified most the equipment already but the one question I have remaining is that of the analog sensors. I want to use 6 water level sensors, at least 4 soil moisture (hygrometer) and then a I would love to use a windspeed sensor input as well.

With my understanding the system can only supply 200mA for the analog system, I am overcoming the minimum supply by using the power input jack with a 12V 1 A power supply. But all the sensors are 4-20mA therefor if all reach the 20mA signal more than 200mA will be drawn.

Could these be supplied from another 5V source and the GND be bridged to create a common ground as done with other systems? >:( I read this should not be done for the 8 relay module so assume it can also not be done here?

11 sensors? What board do you use? If a board can handle 11 sensors, one would think it could provide power for them, too. If not, I guess you can provide the 5 V voltage to each sensor from a different power source than the Arduino. Just keep a common ground for all. And connect the sensor signal lines to the analog inputs.

12volt on the DC socket restricts current draw from the 3.3volt and/or 5volt pins to about 100mA.
Anything more will shut down the Arduino and/or fry the 5volt regulator.

4-20mA sensors are usually powered directly from the power supply, not through the Arduino.

You will get no sensible answers without posting a complete hand drawn circuit diagram.
And links to all the sensors.