Ivanovich

You did it correctly.

This game uses a weird FOV scheme, if you leave the FOV at the default 90, you should get an accurate result.

These are all the ways a game can calculate FOV. The calculator will automatically switch to the default FOV and correct method for the game and aim you select.
If you select a different method than the one the game uses, the number in the FOV input field will automatically convert to that method. In the output three FOV numbers will be shown:
Config FOV - What you need to configure in the game to achieve the entered FOV Actual VFOV - The displayed Vertical FOV Actual HFOV - The displayed Horizontal FOV The different methods are as follows:
Horizontal Deg. | 4:3 Base
This is quite commonly used (e.g. by CS:GO), and means that the configured FOV is using a 4:3 resolution base. So if you configure an FOV of 90 degrees in this game, it will only actually be 90 if you are using a 4:3 resolution like 1024x768. If you use a wider FOV like 16:9 (1920x1080), the extra width is added on, resulting in an actual horizontal FOV of 106.26. Horizontal Deg. | Res. Base
This method is accounting for your resolution when configured, so a configured FOV of 90 degrees will actually be 90 regardless of resolution. Vertical Degrees
This is using the FOV of your vertical view instead of horizontal. So if you had a (weird) monitor that was as wide as it is high, and configured this to 55, your horizontal FOV would also be 55. The vertical FOV is always what you configure it to be, and for horizontal FOV any additional width added on compared to 1:1. So 55 vertical degrees = 85.57 horizontal degrees for 16:9. Radians
All the above for radians are the exact same concepts, but radians are used instead of degrees. Multiplier
Some games uses a multiplier instead of degrees or radians. This means you configure an FOV value in the game, that is multiplied by a specific number to achieve an FOV. An example of this is ARK, which when configured with FOV 1 is using a multiplier of 90, resulting in an FOV of 90. If you set it to 1.2 the FOV will be 108 and so on.  Now for games that support it, you might want to configure the FOV as close to your preference as possible. This is where the calculator comes in handy, as it will do the conversion job for you. Say you prefer the FOV of H1Z1 of 67 Vertical Degrees, and want to achieve the same FOV in Overwatch. Simply select Vertical Degrees for Overwatch, and enter 67. The output will tell you that you need to configure Overwatch to FOV 99.28 to achieve this (if using a 16:9 resolution).

FOV is a part of the calculation so it's important that the configured FOV is used, but you do not need to match FOV's between games to get the same Viewspeed sensitivity.
But the closer the FOV's are, the more similar the sensitivity will be. This is obviously not possible for ADS and scopes, and using the same FOV is not possible on all games. 

Viewspeed (and Monitor Distance) matches what you see on the screen, so the further outside the field of view you get, the more the movement will differ.
The discrepancies in the calculator output is only due to the games inability to accurately match the sensitivity. For instance with Overwatch, the 0% discrepancy sensitivity might be something like 7.23454, but since the game only supports two decimals, the output will show you a sensitivity of 7.23 with a discrepancy of 0.0605% (0.0015 inches). Usually this number is very small and insignificant, but it's worth paying attention to it if it's several percent. The way to fix it is usually by adjusting the DPI of your mouse if it supports it (i.e. try changing the DPI of the output game until it's perfect).

Yes.
Yes.
Targeting is holding right button, and it uses the same FOV and sensitivity as Hipfire, so it actually doesn't matter. This value should be the same as Hipfire/Normal.
Yes.