A few beginner's questions: Recommended amp/Audio-output toggle via switch

[nikogit2022]

I'm thrilled about this project and the prospect of not having to buy a toniebox! So I'm planning on building my own phoniebox and came up with a few questions:

1. Recommended AMPs?
   From what I understood basically any amp should work (hey, why not), but I would feel more comfortable buying one that has proven to work (trouble free)? Is there such a list? The wiki seems to contain only information on how make certain amps work? Or more specific: Did anyone successfully use this one: https://www.adafruit.com/product/3346?

2. Audio-Output Toggle
   My idea involves a switch to toggle between speakers and headset (jack or bluetooth) as I don't want to use leds/led-buttons.

a) Functions to call for the toggle
Bluetooth toggle should work out of the box with 2.3 (1262 ). For toggling between headphone jack and speaker I have to follow 1638?

b) Creative use of the GPIO control
The GPIO control or at least its documentation focuses on buttons, but it should work with a switch - please correct me if I'm wrong:

Solution 1: Making Use of the edge parameter (set on "both"), this would call the function everytime the switch is switched (and the signal changes from high to low or vv).

Solution 2: The switch is to be connected to two pins so that they are activated depending on the switch's position. This would be equivalent to two buttons pushed on hold alternately. Now both of the "buttons" can be connected to the toggle function, so each time you switch the switch the toggle function will be called once? Is that correct?

Thanks a lot everyone!