Well, I just had a look... and it seems some of them are 'discontinued'... with iOS updates, app developers eventually get forced to either update their app, or else it 'disappears'...
Personally, I've been using TBMS, TB Midi Stuff, for years. It's great, but not perfect... it's at v2 atm, and v3 has been delayed for YEARS... anyhow, it's still quite cheap and really neat...
Then there's Lemur... which is also great, but takes more of a programmers knowledge to get around. Lemur is basically like DOS-based programs or the like. To contrast, TBMS v2 is more like a 'Windows 3.1' version or something... what I'm saying is more complex stuff is possible with Lemur, but TBMS is more user friendly, and can be programmed solely on an iPhone/iPad. And some quite complex programming can still be done.
If you want to be in complete control of your interface and setup, I can highly recommend TBMS. Though you probably have to spend a couple of hours at least, the first time, to make your own custom interface...