For the wifi, there are 2 cases:
- Real disconnection, it will not automatically recover.
- Temporary interference with other wifi, there is automatic recovery.
The first is more related to a bug or rare circonstance I would say as it should not normally not happen. The Spark will stop after a while (if not in ATTI mode). With ATTI mode, braking is under pilot control, not the Spark so it is where the thinks could go wrong.
In the second case, there will be lag in the control, the time for the RC to send successfully control commands to the Spark. In the mean time the Spark will still be flying and the main risk is to over react in controlling it.
Regarding automatic change of channel, I don't know but a short test with phone and Spike linked at 2.4G, show one channel used on my scanner at high level, at least it is the video feedback I would say. Control and telemetry could be on another channel but that would mean 2 wifi connections. Also the Spike + RC don't look so good at selecting the best channel in auto mode. It was just at same channel as my main wifi at home where there was other channels with much lower disturbance.
Using prop guards during the learning curve time is for sure good, that is not 100% protection, but it can really help.
To practice skill of flying indoor, nothing best than a cheap quad (30$) that fly only in ATTI mode. That will reduce the fear of flying indoor with a bigger quad.