I'm not sure where that particular app comes from but there haven't been resort buses at the TTC for as long as I can remember! And I've been going to WDW several times a year since '99!
I'm not at all sure that there isn't a bus to FtW from MK. There is a bus from MK to WL...so one would assume that there would be a run to FtW as well. But yes, you can use
ECVs on most of the boats..especially the larger ones.
The Twiz app is a Disney world transportation app you can put on your phone or tablet. It lists all locations from resort's,parks and dtd. You just select your starting point the ending point and will give you at least three options of transportation with times. All locations show correctly on this app except fort wilderness. It seems to think there's no direct bus from mk to the campground. But others than that this app works great in judging how long it would take you to get from the parks to your adrs if there at other areas of wdw