I hope that I am not too late but I just saw your post. I would vote for the non-bulkhead so that you can lift the armrest if needed. I have also found that the bulkhead can be an issue b/c you have to put your bags in the overhead bin so you can't easily access items.
You are correct, however, that there won't be any floor space in the non-bulkhead seat. When I flew long-haul with my toddlers they were either buckled in or we were walking the aisles so that wasn't an issue but you may travel differently.