Please find answers to your queries in the same order -
- HFSS is used for any arbitrary 3D model simulation whereas 3D layout is especially used for devices whose thickness is very less when compared with the other two dimensions. So for your case, you should use HFSS.
- Use normal HFSS. You will still get exact same results even if you use Hybrid and array solution type. As the name indicates Hybrid and arrays solution type is explicitly favourable for arrays and hybrid regions.
- Modal and terminal are two types of driven excitations that you can use. Using the modal type, you can set up the excitation as per the mode whereas in the terminal type, only one mode is excited. In your case, you would get the same results for both types.
- All are geometrically equivalent and you can choose any of them. Care should be taken while defining manually as certain air padding is a must for radiating models.
- For a given model, all of these provide the same result. Care should be taken while selecting one from these. In your case, you can choose any.
- As far as the geometry objects are equivalent, you will get the same result. These are the drawing options for designing models. Choose any as per your convenience.
- Metal thickness may or may not affect the simulation results. Using 2D objects for metal traces is not a wrong simulation. It will only affect the simulation accuracy with a decrease in time to complete the simulation. Use as per your convenience.
In conclusion, you will get similar results as far the simulation setup is identical to each other. Please go through our Ansys Innovation courses to clarify your doubts - Intro to Ansys HFSS - ANSYS Innovation Courses, Microwave Passive Component Simulation Using Ansys | Ansys Courses, Microstrip Patch Antenna Array - ANSYS Innovation Courses.