How can I integrate SSL on my website?

There are many routes you could take this with different membership plugins or subscription based plugins which would accomplish what you are looking to do. However, the best starting point for you is probably using an LMS (Learning Management System) plugin or theme. An LMS will provide everything you need out of the box and will be scalable for your future needs as you develop more courses, integrate quizzing or surveys, award badges or certificates, etc. The LMS will integrate the membership or subscription tools you'd find in those plugins with all the other tools you'll need to create your coaching course. Let me know if you want to dive in more.

Most of my friends use www.wordpress.org and http://member.wishlistproducts.com/ to create their membership sites. Hope that helps.

Cross linking refers to the process of linking between two websites. Whether or not they are owned by the same person, cross linking is the process on which the internet is built. It allows users to reference sites with content similar to that which they are already viewing, and may be of further interest to them.

Go for Wordpress initially. -- Custom website will delay your launch plans considering all factors. -- Wordpress can be used to meet your requirements from day 1. -- Once you have enough visitors and decided the revenue model + business objective plan for a customized website to be developed from scratch.

I would recommend that you check out http://wistia.com/ - I use them for all my videos. Public and privately.