Personally don't think a staff should log if they aren't going to actually be there, or if they do they should use an alt. So if someone tries to contact them via. importance and/or need help they can knowingly get a response quite promptly. It's not lack of staff of inactivivity. It's more all staff are from similar timezones. So this becomes an issue when it becomes nighttime, food, social hours etc. I believe it's handy having young staff amongst the team also, as they are young and high spirited so that's a plus side to the staff team as-well as the older more mature and knowledge-able staff.
They are a good team when they work together, but it somewhat lacks at times when it comes to communication there isn't a bond quite highly apart from Santa, Max at times and that's mainly all i PERSONALLY see. When people see their names they shout and praise like oh yay staff, how's it going, can you help me with this, that oh they're awesome and hound them constantly with questions and curiosities, needs more build like this amongst the two imo. But i could just be waffling
my thoughts and honesty.
If there is more staff, perhaps consider timezones so you're not going to bung more people into the same area.