The small iPhone charging brick should be able to charge the iPad but it takes much longer. Additionally, when the screen is on, the charger barely feeds it enough juice to compensate for whats being used so that may explain why the charge is not going above 3%. You could turn off the screen and let it charge overnight and that should suffice. If it doesn’t charge at all, even with the screen off, that may be indicative of a problem with the charge system (charger, charge port, charge circuit).
Hopefully you ordered an original Apple or MFi certified charger, cheap chargers can damage the charge circuit.
As for the Home Button, if the Touch ID no longer works, you may have damaged the HB or flex cable. Take a close look at it, preferably with magnification. Look for tears or any other form of damage. Even the slightest damage can cause issues.