Ah man sorry...I hear you, it's a fine balance with the wife. She still nags me all the time but deep down she knows I need it. What if you kept the big one and got rid of the smaller tanks?
The sump does fit underneath- however, most aquariums this size will require a big skimmer, which won’t fit unless you go for a very low profile skimmer. Alternative is to go with an external skimmer.