Easiest way to configure landing page linking out to different urls?

Hi,
sorry in advance if this makes no sense or is completely obvious. I have a streaming cold and have probably over-thought this by now but I know I wont rest until it’s figured out.

In my mind it goes like this:

* myname.com: Landing/Homepage really simple with header and then links out to following:
** myname.com/about: A static about page.
** mynamebooks.com: Author website.
** differentname.com: my blog. Catering to a wider audience and designed to create a unique brand experience. E-commerce (digital products).
** differentname2.com: forum.

So is it best to a) create them all as sub domains using multi-site. And if so, would it be possible to point the individual urls at the sub domain urls. example: differentname.com >> differentname.myname.com

Or, is it better to just create single wp accounts for all and link accordingly. If so, how would that work? Would I be able to use the same email for all of them or would I have to have a separate one for each? Seems like a lot of work.

Ideally I’d like to work under just one ‘hood’.
If you have any ideas or experience with this please let me know what you think and thank you for reading this far. ??