#1 and #2 Simple, either a 2nd class ticket (half fare if you have a half fare card or GA), for the distance you transport the bike OR a SBB Bicycle Day pass which is CHF 13 half fare or CHF 20 normal price.
A - At counter, ticket machine, online, mobile app (at least the day pass should be possible with the app).
B - See above. You have to decide which option is cheaper in a particular situation.
C - That is not a question, so this is not an answer.
D - Just try it and see whats happening if you buy two tickets on your name for the same distance. If all fails see A.
https://www.sbb.ch/en/abos-billette/...obillette.html https://www.sbb.ch/en/station-servic...-with-you.html https://www.zvv.ch/zvv/en/travelcard...transport.html
and also rules regarding rush hour
https://www.zvv.ch/zvv/en/travelcard...-bicycles.html