Will this work

Hi I am only moderately technically inclined so bare with me.
I want to set up a basic system where I have a menu with 2 extensions that are forwarded to cell phones. I also want to be able to use my mac as a sip phone and a fax machine. I know of a few software options for both I am mostly just wondering if running my phone line through asterisk will hinder any of this.

I am also trying to choose between Vonage and Zingotel I live in Canada and these seem to be the best options.

For just the two extensions it is no big deal. Faxing is a bit more complex. By using Vonage I think you defeat the entire point of asterisk and VOIP. It would be a lot more efficient to have your box register directly with an ITSP. I f all you need is two extensions forwarded and faxing PM me. I think I can provide a cheaper and easier solution.