Here are the answers for b):

- you'll be able to skip all adverts

- the game only contains only rewarded ads, which means that you can choose when to watch them and it gives you an in-game reward for doing so. Most ads have a cooldown though, ranging from a few minutes to a couple of hours.

- you can use up to 2 research speed up ads. Afterward, an 8-hour cooldown begins.

- yes, it works if you have no wifi

- the amount of rewarded ads in the game stays the same, but they are not displayed and you are rewarded immediately. This doesn't use mobile data.

Note: there currently is a bug where you cannot speed up research if you have no net, but it can be circumvented by clicking on the 3 dots next to the research and speeding up from there.