Matt, I had a similar problem come up in the past. Unfortunately, it seems that these types of problems plague Belkin Wemo users. I tired everything you did and restored every device to factory settings. I uninstalled and reinstalled the Wemo, etc. Nothing seemed to work. The only workaround I have found is to set a rule to turn the light switch off. This was also Belkin's Support answer. It's just a fix for a symptom though, and not solition to the problem. If you ever find a solution, please let me know!!!!
Unfortunately Error 53 is not a correctable issue. It is probably related to the replacement of the Home Button on the iPhone 6/6+; however, there is not accepted solution to the problem. If you saved the old Home Button assembly, you could try reassembling it back onto the new display assembly to see if that resolves your issue.
This website does not actually provide repair services; however, there is a guide available to show you how to replace the battery here: iPod Nano 6th Generation Logic Board Assembly Replacement. That is the guide for a logic board replacement, but it will show you how to remove the battery in the guide. You can also purchase a new battery here: iPod nano (6th Gen) Battery.
Yes, the RAM is upgradable. There is a panel that can be removed that is located on the bottom of the computer situated next to the Windows Product Key tag. It uses DDR3 PC3-12800 RAM with two slots available. Each slot can hold a maximum of 1 GB, so you can upgrade to 2GB. The RAM modules can be changed out in under 5 minutes.
The problem with trying to replace the flex cable is that the cable is tied to the logic board of the iPhone for security purposes. I have not personally soldered a flex cable or connection back together, but others have. I believe there are six connections that must be soldered.
If it's an iPhone 6, then it will still be under the warrenty period. Take it to an Apple Store and have the Genius Bar take a look at it. Should be covered if it's the battery, and you won't be out anything.
Are you getting any response when you turn the ignition? If not, it may be your starting solenoid or spark plug. Both are sold as replacement maintenance parts at most retailers who carry lawn and garden supplies.