The sailing time for the fast ferry is about 5h

The catamarans do not operate at that time of the year, they operate from around mid-April to mid-October, outside of this period, you only have the option to take a bus from Dubrovnik to Split. The trip with the bus takes about 4 hours.

For sure not, as there are no trains between the two cities.

On the departure with Krilo catamaran you can bring a bicycle but only if you purchased a ticket for you and the bike upfront, as the space is limited.

Jadrolinija and Krilo have individual rules for cancelling tickets purchased online, so you will have to check the cancellation policy of the company you have booked with.

You can see the rules for bringing a pet on the Krilo catamarans here, and for the Jadrolinija catamaran here.

Seating on board the fast ferry is free, but as Dubrovnik is the first port on the trip, you can get seats next to each other if you make sure to be early in line for the boarding in Dubrovnik.

Yes, there is a coffee bar, where you can buy drinks and snacks.

2023 Dubrovnik to Split Ferry Prices

Below you can see the 2022 summer price lists for the catamarans from Dubrovnik to Split.
Kapetan Luka- Krilo catamaran ticket costs 45 EUR one way, while Jadrolinija catamaran ticket costs 38 EUR one way. There is also a TP Line catamaran operating for 45 EUR.

Dubrovnik – Split 2023 Jadrolinija Catamaran Prices

Dubrovnik – Split 2023 Krilo Catamaran Prices

Dubrovnik – Split 2023 TP Line Catamaran Prices