If you kill network access, sure. I don't think the software itself makes any guarantees about data privacy. For me, as a linux user, it's more effort to get windows vms for these things, but I do them because the desktop ones are often cheaper.
Sure. Like many things, local software is necessary to preserve privacy but not sufficient. Local proprietary software can brazenly work against the interests of the user, libre software can contain backdoors or other antifeatures, a peer-reviewed libre system can be cracked. But by heading in this direction, you retain the possibility of keeping your personal information as private as possible.
FWIW I'm a Linux user that runs most everything in VMs. Each year I create a new one for TurboTax, get the updates/stateforms, then disconnect and never reconnect it to the Internet. It's a little work, but can be done mindlessly while doing something else.
I take it that you send the forms by mail then ? Because efile would need network access, and that is half the reason I'm using the tax software in the first place.
Yep. The time of going to the post office is dwarfed by the headache of actually doing the taxes and checking that they seem correct. Disposing of them into the mail is downright cathartic.
