also the IR sensors have a analog output. Is that same to plug into the arduino's analog pins?
If the sensors won't generate more than 5V, it should be safe. (Generally, they're all less than 5V. However, verify this...)
My question is if it is safe to simply use that power source without some sort of resistor between the power source and sensors?
You probably don't need a resistor*. Current is supplied on demand; if you need 1A but have a 2A supply, only 1A will flow. Voltage, however, is constant.
That being said, some parts will pull more current than they can safely use (like a LED, so then you would use a resistor.
This should all be found on the datasheet (especially with a more trusted brand like Sharp). Just look for example circuits and input voltage/forward voltage. A quick note, make sure to connect the grounds if you're not driving the Arduino directly from the power supply.
*There probably is an internal resistor for the LED. Again, datasheets, datasheets, datasheets!