That setup is missing this piece from the first post:
to remotely control equipment all over your house
You can already buy an inexpensive android phone that does all the rest of it. Some for as low as $10 and some with lots of features for $20 -$30.
There are already community members using those, no reason to build your own.
And you can do a nice looking tablet for just a little more.
@beckwith has a project report on a very nice one, but there are others described in the forums as well.
So there are quite a few options, but once you drop the direct device control and just go to Wi-Fi and Bluetooth interaction, I think I’d personally start with a phone. You get a lot more options at a similar or maybe even lower price than trying to build it yourself from parts.