Winners will be 320/321, 738/739 and 753 all in high density configs.
When you are very close in numbers there are always some small elements - for example a320/321 with v2500 will be heavier than with cfm56. Around seats options now there is a titanium frame bench which is twice lighter than typical triple seat block. There are a320 with only 2 toilets iso normal 3.
Widebodies are always heavier per seat.