GoDaddy ‘Search Engine Visibility’ All-in-one SEO plugin: a good combination?

Hello,
I will shortly be opening a wordpress blog and the only SEO plugin I will be using is the All-in-one SEO plugin as I have been advised to use this one and ONLY this one as using more than one SEO plugin would be detrimental to my search ranking.

I have decided that I want to use GoDaddy as my hosting provider. I have noticed they offer a service called the ‘Search Engine Visibility’ plan. I am seriously considering taking out this plan as it seems GoDaddy don’t allow your website to appear on search engines otherwise.

So here are my questions:

1) Is it true that I should only use the ‘all-in-one’ SEO plugin on my WordPress blog?

2) Should I purchase the GoDaddy ‘Search Engine Visibility’ plan and use it with a WordPress SEO plugin?

Thanks in advance for your help.