Can I tie both INHIBIT and ENABLE to 0V ?
No. The normal operation is that INHIBIT is inactive (HI) until you want to
read data, when you wish to read data, you take INHIBIT LO (preventing updating
of the output latches during the read) and ENABLE LO (presenting the data in
the latches to the output pins).
You may not tie both INHIBIT and ENABLE to 0V as this means INHIBIT is active
and will prevent the transfer of the data from the up-down counter to the o/p
latch. But you may tie INHIBIT HI and ENABLE LO thereby allowing continuous
reading of the output data lines. By disabling the INHIBIT you do run the risk
of reading invalid data during an update of the output data.