Given any collection of $n$ distinct circles in the plane (with fixed but possibly distinct radii),
is it always possible to rearrange the circles so that any two of them intersect twice?
Given any collection of $n$ distinct circles in the plane (with fixed but possibly distinct radii),
is it always possible to rearrange the circles so that any two of them intersect twice?
Yes.
Arrange the circles such that they all share one point $P$, and that any pair of centers are not collinear with $P$.
Any pair of circles will now intersect at $P$ and one other point that is the reflection of $P$ across the line between the circles' centers.