arduinopi:
It still does not feel safe using a switching regulator knowing it will be pulsing 12 volts to "5 volts".
The output of any decent, properly-designed 5V switching regulator is just fine, regardless of what the input voltage is.
can I really use a switching regulator at 12 volts for any electronic device that uses 5 volts?
Absolutely not! A 12V switching regulator supplies 12V!
will a switching regulator damage any electronics? Does a switching regulator lower lifetime for the Arduino or any other sensors?
No and no.
I plan on using a 7A switching regulator for all my 5 volt devices will they all be okay being directly connected to the switching regulator?
The amperage that the regulator will supply is not the issue. If you have a 5 VOLT, 7 AMP switching regulator of decent pedigree, then all should be fine. And you'll be able to power one truckload of Arduinos and sensors with it because 7 amps is a relatively large amount of current.