Hard to answer. You will have some control on scheduling, but may find it easier in some ways via the web app.
The 4-tuner Tablo transcodes audio to 2-channel, so the answer is no.
Generally speaking, tuners in TVs are usually better (not always the case). This is because of patents, etc.. Hard to say with regards to Tablo as there are huge amount of variables especially when dealing with OTA and something that is considered to be "marginal".
Shouldn't be a problem.