Will be brutally honest with you, Magento2 provides no extra business functionality over Magento1, it's a technical update and as such it's a long way behind in terms of extensions and knowledge. Nexcess are a very good host, one of the best, but you need to pay for quite a good setup to get the results, we don't do any Magento2 installs as the architects decided Magento2 wasn't up to scratch and didn't provide a return on investment. It's ok if you're a new small store and have time to fix the issues as you go along, but if you're a business 1.9x is more mature.
For the hosting, we use Amazon AWS, it's easier to scale up and down and with a good cluster can index 30% of the site within 1wk, but you need to know what you are doing with it. Unfortunately the consultants stopped doing installs last week until Feb/Mar as it will be difficult to see a return on investment this year, they do installs in a few days, otherwise for $4k could have had you up and running with AWS mini-cluster, Excel direct product uploads, seorealtime.site (does the same as hiring an seo agency), etc. Launching in November means you will not have the time needed to get everything up to speed, customers and crawlers need time to trust your new site.
Configurables are a pain, we try and avoid them where possible and use options, again it comes down to productivity as product uploads and inline product maintenance are more complex with configurables. With Magento1 there are some extensions which allow holding stock at option level in the product, and our (well not technically ours) Excel direct product upload works with options. It explodes fashion and beauty products in to Magento and managed from Excel, we just drag drop the new file and it auto syncs. This doesn't work with configurables and you have to use solutions like Magmi, which again is a technical product where you need programmers, with Excel it can be maintained inline by business people.
It depends how much time you've invested in Magento2 and whether you can write it off, but in reality Magento1 is a better business choice and Magento2 a better technical choice, however business drives revenue, technology is just there to help and with Magento2 you will be fighting it a lot of the way.
