First I presume the mast is down.
When you start removing bulkheads you run the risk of looseing the fairness of the hull if there is any loading on the outside that the bulkhead was countering. The mast column may be removed without harm but must be replaced before the bulkhead is rebuilt.Learn the "tick stick " method of taking off shapes. You have the opportunity to make the interior the way you want it, so now is the time to get creative. The space under the "vee" berth can benefit from the addition of shelves. This is a good time to look at how you will ventilate the space. Access doors are more convenient than hatches under the "vee" berth cushions but don't eliminate the hatches.Headliners don't suit me so I shall let others weigh-in on those.When I built new bulkheads for Bietzpadlin I cut handholds into the edges and find them helpful for places to grab when entering and leaving the berth and when the seas are a bit bouncy.