Every variant gets 60:40 split fold seats and rear air-cond vents but that's where the similarities end. Apple CarPlay and Android Auto is available on the E, V and RS variants, LaneWatch is available on the V and RS variants. If you want the best of the best though - including Honda Sensing - then RS is the variant you should go for.
Yes, Honda City is available in Engine Start. The available Engine Start variants are: 2019 Honda City 1.5 E, 2019 Honda City 1.5 Hybrid, 2019 Honda City 1.5 S, 2019 Honda City 1.5 V.