No, they only communicate every 15 minutes and only when in range. So, if the handset is brought out of a cupboard it may not communicate immediately and may need some catch up time. This can be actioned immediately by pressing the back button.
No it isn't and you will have to reset the time in spring and autumn to the correct time. Likewise the handset will need to be re-programmed for a leap year.
No, the AIMS unit will do that for you; you will only need to enter the time that normal temperature is required.