Where did you check SSL? I see it is working on your site.

Site stitch to SSL automatically when you login or go to registration. Only customer section and checkout pages are using SSL, not all product or catalog pages.

If you need whole site to use SSL all the time, you can can configure main URL in configuration to use HTTPS.

Thank you for your feedback.

It is definitely a great idea.

We will need help with implementing mentioned Payment gateways for AbanteCart.
Feel free to contribute. 

Express Checkout is just adding button to go go paypal to pay. I think it is equivalent to standard paypal account.  Paypal Payment Pro is next level.
https://www.paypal.com/webapps/mpp/compare-business-products?nav=2.0

What version of PHP do you have?

It looks like you do not have mbstring PHP extension installed or enabled.

mbstring is a non-default extension. This means it is not enabled by default. You must explicitly enable the module with the configure option. See the Install section for details
http://www.php.net/manual/en/mbstring.installation.php

So, you might have to enable that extension, modifying the php.ini file (and restarting Apache, so your modification is taken into account)

In AbanteCart you have ability to set up product Length, Width, Height and Weight. These are set up on product and product option level. 
Depending on the shipping method you will be using these parameters will be used to calculate shipping cost.

What error do you get? What payment method is set up?

Yes. I am aware of drop shippers and services. What do you suggest or propose?

Thank you. We will nail this problem some other way.

let us know if you need help with template creation. just create new topic. FYI. Templates can be as extensions, there is free extension as example.