What is your checkout workflow ? Could you send us an FTP access to your website so that we can check the problem of the checkout being stuck on the shipping page ?
The fact that the confirmation emails takes so time to come is normal: First, hikashop needs to wait for the notification from paypal. Second, once hikashop sends the confirmation email, your email server need to contact the recipient server and that can induce a lot of delay. On HikaShop's end, confirming the order and sending the email takes less than a second.