attachInterrupt and arduino to arduino communication

I am currently making a sensor module that combines 5 light to frequency converters into a unit that would be able to take light intensity readings from multiple directions without rotating. The idea is to put this on a rover with an arduino uno (which is going to be doing a bunch of other stuff) and periodically stop and scan for light sources.

There are a few problems I am faced with at the moment that may require me to rework my plans.

The light to frequency converter code I have been using requires an attach interrupt to get an appropriate reading. The code currently attaches when reading is initiated and detaches when complete. Is it possible to attach and detach on more than one single pin. ie. take reading on pin 3, then on pin 4, then on pin 5 etc. - From what I remember reading somewhere arduinos only support a few predefined pins for being “attached”.

Would it be more practical or even possible to plug them all into their own analog pin and take an analog read? Would this work to accurately grab the frequency? the meaning on the number doesnt matter to me as much as the relationship between one sensors number and the next. It is just for relative positioning.

If it is not possible to set each sensor to its own analog pin, my thought was to get a second arduino (one of the smaller variations if it supports cross communication) and have it continuously cycling through each sensor and getting the values in the background and then transmit the orientation of the highest valued sensor. Taking a reading on one sensor as it is now takes only about 1 second to sample and convert but if I have 5, thats 5 seconds of doing nothing while the attachInterrupt is active to get all the readings and then make a decision on where to go. (it counts the pulses so the active function would override anything)

Is there an easy way to do arduino to arduino communication?

I just had an afterthought regarding this. If I set up a software serial on the main uno and just use the regular rx/tx pins for a 5v pro I could just communicate that way right?