>>2055109There's variation between frames, but basically you either run full housing from end to end (simple, but adds internal friction for cables - totally fine for hydraulic lines and electric wires though) or you have cable stops on the frame and the cable runs from point to point inside the frame. The easiest way to explain this is to look at any old CX frame with all the cables external: the cables run inside housing where they need to make bends, but run without housing from point to point between cable stops that anchor the housings. Internal routing is the same thing but with the cable anchors and routing path moved inside the frame. Typically you'll have plastic liners over the cables inside a frame to prevent noise from rattling if there's any slack in the cable.
>>2055000As long as your chainline is perfect for one of those cogs or aligned to the middle of the 2x fw it should be close enough. Just make sure your chain is the right length to work with all 3 ratios within the range of positions available within your dropouts.
>>2055008Entirely in favor. Electronic shifting is a better user experience when it comes to consistency and reliability. It's more friendly for beginners, casuals, and anyone with less hand strength or just smaller hands.
>>2055072Microshift only does cable brakes in their lineup currently, so it would have been a double leap for them to go hydraulic with.