Can Kepler's laws apply for circular motions? (First law states planets take an elliptical orbit)
The circle (eccentricity $\epsilon = 0$) and the ellipse ($0<\epsilon <1$) are two of the four conic sections; the others being the parabola ($\epsilon = 1$) and the hyperbola ($\epsilon >1$).
All four conic sections are possible trajectories for orbits with the Sun at one focus.
You can think of a circle as a degenerate ellipse with the two foci that an ellipse has being at the same position for a circle.
The equal areas in equal times law is also followed for all of the conic section orbits as angular momentum is conserved for each of them.
The period -distance law is only obeyed for the bound obits - circular and elliptical.