You typically see 3 links in the front with a panhard. Not triangulated 4 links because most people run a steering box with a draglink. The draglink pivots at the pitman arm and the other end moves in a radius up and down. When you run a 3 link with a panhard bar the panhard bar pivots on the driverside frame rail and the other end moves in a radius just like the draglink hence the reason they should be as close to the same length and parallel at ride height and throught the range of travel. If they weren't then the axle would move in a different radius than the steering causing bump steer. If you were to have a triangulated 4 link the upper links locate the front axle centered under the vehicle instead of the panhard. They actually cause the axle to move stright up and down with no side to side movement, that wouldn't work well with conventional steering. If you have full Hydro steering a 4 link is great because there is no mechanical link from a steering box to the axle. There are different variations of 3 links like doing an upper arm thats a big triangle with 2 pivots on the frame and one on the axle so this stuff isn't necessarily true for all 3 links but you get the idea.
In the rear you could also have either style. Typically I would prefer having a tri or dual tri 4 link because of 2 things. 1 more links = more strength, and 2 the rear axle tracks more in line with the front. With a 3 link and panhard in the rear the more the suspension loads or unloads the further the panhard will move the axle right or left of the path of the front axle. I guess in the rear it all comes down to how much space you have and what characteristics you want. Conversation about link suspension can go on forever cause there's just so many different things you can do so I hope this helps some.
