Question 1:
Let's treat the particle (assuming positively charged; just flip the directions for negative charges) as if it's at the axis (or very, very close to it, compared to the radius of the loop). Then the magnetic field of the loop is pointing down (away from the center of the loop, towards the particle), so the force on the particle (right hand rule) is into the page. This causes the particle to move in a circle in a plane parallel to the plane containing the first loop, but in the opposite direction. Then the particle generates it's own magnetic field. This field is pointing up on the axis of the particles's loop, but then curls away from the axis to wrap around underneath (this is the magnetic field of a dipole, I'm sure you've seen a picture of it). Then at the loop itself, the magnetic field has a radial component and a vertical component. The vertical component causes a radial force on the loop; this cancels because each part of the loop has force equal and opposite to the part of the loop directly opposite it. 531
The radial component of the magnetic field induces a downward force, pulling the loop towards the particle. So in total we have a magnetic force on the particle pushing it in a circle, and a magnetic force from this circle on the loop pulling it towards the particle. There are higher order corrections that can be made based on the magnetic field caused by the current loop accelerating downward, but those are usually quite small. There isn't an upward force on the particle; <PERSON>'s third law doesn't apply directly to magnetic forces, because they don't act along the line connecting the charges. In trying to understand magnetic fields and forces, I would advise staying away from the "North pole/South pole" idea and instead work with vectors, because then there is less possibility for a conceptual error (just make sure to keep track of minus signs).
ADDED: Question 2:
I don't think "synchronizes" is the right word here. The charges are not necessarily moving at the same angular velocity as the particle; they are almost certainly slower. They do circle in the same direction, if you assume that both positive and negative charges are moving in the loop (this is possible, e.g., in plasmas, but in wires it is just the negative ones). Did you mean something else by "sychronized"? 531