Developing SharePoint Online website for Anonymous users

Microsoft  creates one public site collection per tenant. This public site URL will be like livecompanyname-public.SharePoint.com

We cannot create child sites in this public site.

 There is currently no best way to develop a second public site collection for anonymous users in SharePoint Online.

Following are alternatives we can have
 You can enable external sharing on admin side and create a site collection with Sharing enabled for anonymous users. This site collection allows sharing the site to anonymous users by invitation.
These anonymous users can only have Read-only access based on out of the box functionality.
. If you want to capture data from anonymous users for this type of site, there are three alternatives

1. Modify the contact form so that we can capture the fields that we need.
2. Use the following web-part or write something similar to create a contribute privileges .   https://anonymous365.codeplex.com/releases/view/105618
3. The external user can create a live account and use that to login to the site. This live account in most cases can be treated as a normal AD account in office 365 and can be given contribute privileges. The problem with  this approach is, the site is not truly anonymous like the one we specify in SharePoint 2010. We would have to share the site to the user's email Id. 

Thanks
Nate