Anna, there can be couple different problems: 1) LCD you installed was defective (or damaged during installation, trust me that's common for DIY) 2) LCD is not plugged in correctly to the board ( you can try to open it and re-attach the LCD connector to the board and restart the phone holding home+power button) You can also check, if you still have the old LCD assembly, you can connect it from outside bu just disconnecting cables for LCD installed on the phone at this time and bend them back so you can give enough space for different LCD to be connected just plug it until you hear/feel the click and try to power on the phone. In case this will work you might need to replace the LCD screen assembly . 3) LCD connector on the board is broken (see if this was not damaged during installation) 4) Yay! any water damage???
You need to replace headphone jack cable in this case. You can confirm that microphone used for talk on loudspeaker is broken by recording a video. See if it records any sounds. If nothing happens or it makes noise - replace headphone jack cable
if you remove glass carefully without jamming old stickers you can stick the screen to old ones and it will be fine. just make sure not to touch them to much so it still remain sticky. If not you will need to get a new double sided tape stickers
When you switch to a home screen and try to press volume buttons up and down, will the volume indicator show up and move up and down? Sometimes it happens that charging port has a short and phone thinks it is plugged to the dock station, and it does not play music trough loudspeaker as well as does not allow to control volume of the phone. If you have this symptoms i suggest you to change charging dock cable, this should fix the problem V.
For home button most likely home button flex cable was broken during the installation. Regarding reception check this picture make sure antenna is clipped on its place correctly and small circle antenna connector is still on its place, see also if small blue color coil on its place as well as small brown resistor next to it any of this 3 will give you a problem with reception if damaged
i had a repair on iPad 2 recently, in that case it was weak connection between LCD and LCD cable, had to clean it and reconnect. It worked fine. But there is also many other possible options can be as well: 1) bad LCD 2) water damage 3) problem with motherboard (backlight filter and some other ICs)