but do not understand the start.php registration of a custom register page

elgg_unregister_page_handler('register', 'elgg_user_account_page_handler');

elgg_register_page_handler('register', 'custom_user_account_page_handler');

Look at elgg_user_account_page_handler() to override it with your custom function.

Also, you can try Profile manager plugin which included the validation and custom forms already (use latest release on GitHub).

@RvR Thanks for the response! 

That makes sense - the only thing im missing now is how to call the view I have in my plugins views/default/forms/register.php instead of "echo elgg_view_resource("account/register");" I don't see how account/register is pointing to their views/default/forms/register. 

If Im missing some overarching concept apologies, but Im new! 

Also I was originally looking into Profile Manager - maybe ill give it another try but it didn't seem to allow me to make custom validation.