Introducing myself and ...my problems.

I would doubt there is anywhere in the world where you could connect and disconnect services on a casual basis. Certainly not an option here in Italy. The problem you will have is that even if you do connect with one of the providers they are likely to use estimated readings which will assume usage at a particuar level. To avoid this you will need to provide the actual readings, which will require you to be present to make the reading, or have someone do it for you.
For what it's worth I use ACEL for both electricity and gas, but the job was made easier as the landlord worked for them. I too am living on Lake Como, you have chosen well.

Opt for Enel Energia as the other one is going to disappear shortly.  The tariffs mean a saving of a couple of euros or less every 2 months, so dont worry about them.  You will pay for the standing charge, oneri and tasse even if you dont use any electricity.    You want to do a subentro or a voltura taking overthe old contract,  otherwise you will have to pay more.

Two things- there is a difference between resident and non-resident contracts. Non-resident contracts are more expensive. Secondly, yes there is always a standing charge, even if you use nothing. Taking over the old contracts may be more expensive, but easier. Good luck and learn some Italian!