Try Settings App>Sounds>Make sure the settings are correct and try to get the Vibrate going here. Reset, hold both Home and Power buttons until the iPhone restarts by itself. See if working. Did you remember to install the vibrate motor? Vibrate motor may have died? Vibrate motor contacts may not be making good contact with bottom of Logic Board? This is a new housing with fit issues already popping up. Good luck.

"If at first you don't succeed, try try again." The fact that your switch wasn't sitting right and that you've have added symptoms after taking apart your phone again suggests that you are not reassembling properly. Go as far into your phone as you did before and make sure EVERYTHING is connected and seated properly. I would also recommend cleaning contacts/connectors while you are in there, it could be as simple as that! Let us know how it goes!