Beau

Hold the option key as it is booting, you may have a recovery partition or it may give you the option for internet recovery.

Can you post a picture of your phone and the battery that you are trying to connect? How many screw holes does the new battery have? 4s batteries have two, regular 4 has one.

That is the light proximity sensor. The other piece is the clip that holds the sensor in place. You need to make sure the sensor is pushed in all the way and then lock the clip into place. This should not have effected your LCD from not turning on at all. Check your connections after you have properly put the sensor back into place.

I use Powerbook Medic. You can type in the Serial Number and they will show you a list of parts with compatible part numbers.

I've changed just the keyboard several times. As long as there are screws you are gold. If its riveted in you are better off with a new upper case. I would also recommend buying a keyboard that comes with the keyboard backlight as it is possible you will rip it trying to pull the original backlight up. I would say this is a very difficult repair. You are going to have to completely disassemble the computer to do this. Good Luck!

You need a new battery for sure, iphones will not go past the apple boot logo without one.

Sounds like the mic is out on the dock connector. The reason they can hear you on speaker phone is because the phone uses the noise-canceling mic near the headphone jack.

You could have knocked the digitizer cable loose. Follow this guide to check the connection. ifixit link

I would not recommend changing only the lens. Get the entire assembly. The LCD and Lens are fused together. This makes it very difficult to remove the lcd without damaging it.

You may want to be a little more specific as to what the piece at least looks like.

Seems to me that the adhesive strips should be marking the score down, not the pentalobe screws. How much more time is that going to add to repairs now that we will have to apply fresh adhesive strips.

Removing the logic board is completely unnecessary and you risk damaging more components. Follow steps 1-3, 11, 20-22, 26, 30-34. Obviously be careful not to damage the board when you are actually taking the display off.