I am not sure if I am data modeling correctly as it seems I am creating a lot of content types.
I want to be-able to have a content page that I can add blocks which i can re-order etc. So for each block I need to create 2 content types i.e:
FAQ Container
QA
So that is 2 content types for a simple block - it looks like i might need a lot of blocks and maybe 100s of content types - or am i doing this wrong?
Could you give an example of the other content types you want to have in the content page?
From what I’ve seen myself, yes, you’re going to have to create a bunch of content types if you want reusable components for your site. It’s pretty hard to work out how to maximize your usage of components, but there are some tricks like having a set of radio buttons and choosing layouts for content that is essentially the same fields, but formatted differently e.g. you have a design with an image on the left and text on the right, another with image on the right, and another with the image above or below the text. All 4 could use one content type with a Title field, Intro text, Image, Text, and Layout. The Layout can be preset radios for each format, then you simply style the front-end according to the selected option.
You could just have one big Rich Text field on your page and add whatever you want (there is an Embed option where you can add existing content and media if you need to). If you have an editorial team this is probably not ideal, though. Too much power is not always a good thing 
Yes makes sense to have generic blocks with a dropdown list to select the type.