1. An electric multiple unit or EMU is a multiple unit train consists of self-propelled carriages and uses electricity as the motive power. An EMU does not require a separate locomotive or an EOG, as electric traction motors are incorporated within one or a number of the carriages.

2. Seats will more or less the same as the same is compensated by no of coaches with ultra modern comfort which I think will provide more comfort than existing Shatabdis.
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3. These are seperate high speed sets and hence LHBs will not come into picture. The LHB coaches might be modified suitably and attached in other required trains having CC facility like Jan Shatabdi Exp or Inter city Expresses. I suppose, ICF CC coaches will slowly be retired from service.

4. EMU sets will ply for short distances between 200 kms to 500 kms and given their faster acceleration & deceleration and capability to reach top speeds in a matter of seconds, the distances will covered in under 6 hours.

5. Loco Reversal happens either during shunting or when the trains mostly Shatabdis are being prepared for return journey which is usually immediate on their arrival.
Profit of EMUs
a. Faster acceleration & deceleration
b. Less Power consumption
c. Lower noise
d. More facilities.
e. Easier shunting & maintenance
f. Aesthetic looks
g. More comfortable rides.

P.S. do not confuse these EMU train sets with that ply in Mumbai, Chennai, Delhi or Howrah Suburban networks.

I hope, i have cleared ur doubts...