Arduino components for smartening my current doorbell
Because you asked for recommendations I would like to recomment the solution I have at home for some years:


Auerswald doorbell speaker sorry for german product description - the a/b is important so that you could use it as analoge phone on 2! You also need a transformator as you should already have for your doorbell.
AVM Fritzbox router
Doorbell or not ....
Two Sipgate (or similar) VOIP accounts


After configuring your fritzbox router and your android phone, your phone will ring and you could talk to the person in front of your door werever you are on this planet ;-)

Just my recommendation....