hey! right now the only supported solution is to use a USB hub. Connect the hub to your iPad, connect Rytm and sound card to hub and you're good.
the next update (this week) will let you choose a MIDI device.
BUT I don't have an iConnect thing so to be honest I have no idea if it works. It will work as long as the device will cleanly pass through all MIDI data from one port to another. Some devices are not really tested to do this correctly with sysex data, e.g. they use a too small buffer and simply cannot handle the larger Elektron sysex messages for patterns or kits.
speed is also a concern: e.g. if you use a USB-to-DIN MIDI adapter of any sort (other than the TM1) you will get very slow MIDI transmission, which will definitely be noticeable in STROM. I'm not sure about speed with iConnect with USB, but should hopefully be as fast as a direct USB connection.
The best connection you can have is wireless via SDS Drop, it's the fastest and most robust, plus you don't need to have a cable plugged to your iPad. 2nd best is direct USB. With 3rd party MIDI adapters results will be all over the place... at best, it's as good as the direct USB connection. But could as well be poor or not working at all, hence I haven't opened this route so far.
Anyway. If you like, You could try and find this out for me, e.g. get an app which can send/read sysex and try if the manual sysex dumps from the Rytm work through your iConnect.
e.g. this is a free app which should display sysex dumps:
first connect your Rytm directly with USB, then dump some sysex from the GLOBAL menu. The app should show incoming sysex messages.
Then, try the same thing via iConnect - does it still show the messages?