Is it better to wait for the touch screen and camera to arrive before installing OctoPi?

Hi, it looks like my Pi will arrive on tomorrow and it will take a few more days for the HDMI based touch LCD to arrive. If I eventually want to use a touch LCD and a cam (Logitech C920x or Pi Camera V2), is it advisable to have all the hardware components connected to the Pi during installation of the OctoPi OS? If I just install the OctoPi OS first and later add these components, will the OS automatically install the drivers?

I would not wait. You may start with the Raspberry Pi and install OctoPi to get familiar with OctoPrint. You can ad the other components at any time.

So once those components have arrived, it will be plug and play?

Not, not as quite as easy.
For basic use, the camera does not need a special plugin, but you have to set some parameters.
The LSD is a bit more complex, but there are some good tutorials how to get them to work. Depends on the model you get.