So am I correct in assuming that everything was working 100% before you started this project?
As far as I am aware, there is, no relationship between the icons being available and/or damage to the hardware. Options within each application may be greyed out, but applications usually still open as usual even if there are hardware problems with the device.
So, you seem to be having an issue with the proxy flex (the flex at the top of the screen). The reason I say that is that the front camera and earpiece speaker are not working. They are both part of that flex assembly, so that is 2 parts not working on that flex, which may be a damaged flex, connector, logic board and/or components damaged around the connector.
Did you reinstall the brackets which hold the proxy flex components in place?
What is really strange is that you have a front and back camera issue. The main camera, connects to the board on its own. Make sure this is seated properly. I would also take the time to inspect the area around where the screen flex cable attachs. It is very very easy to dislodge a few components.
Did you disconnect the battery first before doing anything inside the phone?