OP here....great responses...thanks!
In reality, my response was option 4, until I got super frustrated (because I was hungry and my food was definitely getting cold) and went with 3.
The problem with 3 was that there were no empty tables close by, so I had to drag one across the crowded room (a fair distance). So I was torn between the other options and the disruption I caused dragging the table.
To explain the situation a bit better, the food court has lots of small 2-tops and fewer 4-tops. However, they are arranged in rows so that you can put them together to make bigger tables, or slide them apart a few inches to make separate tables. Because of the way they are arranged in rows, it is impossible to put a third chair at a 2-top. Even if the 2-top was at the end of the row, you couldn't pull a third chair up without blocking the aisle.
Plus, the tables are relatively small...a 2-top only fits 2 trays. Even the 4-tops barely fit 4 people.
I think the tables are designed to encourage eating quickly; not lingering. This is part of the reason why sharing a table with a stranger could be awkward.
The problem I encountered originally was that none of the free 2-tops were close enough to each other, however there were at least 6-7 free tables.
The 4-top closest to us was occupied by a woman on her smartphone with a bag on the chair. I considered approaching her but didn't know if it would be rude. So my kids sat while I hovered with my tray. Eventually, someone left that was not too far away and I was able to drag their table over.