You can always jump between the house and starting. But you're less likely to need that if you have a separate starting battery than using 1 of the house bank. I just use deep cycle or the combination start/deep cycle(I doubt there is a difference). I charge off a dual output alternator with the sense wire going to the house. The starting battery AMP gauge hardly move on start up.

I like having an On Off battery switch for - and next to - the starting battery. Mine is located inside a galley door, and 18" cable away, so no way it will be turned off when the engine is running. I usually use the windlass and wash down (which are connected to the engine battery) before I start the engine. The starting battery is perpetually fully charged. I suppose any type of battery would be fine and starting my engine is easy requiring little cranking time.

The nice thing is then you can run your house batteries on BOTH whether charging or discharging. It simplifies your life.