Hello Drago,
About point two - if I try to reorder a product that is not sold anymore or the order period is over the link that I get redirected to is the following.
http://localhost/mysite/uw-bestellingen/product/listing.
The product listing that is displayed is not an active listing on my website.(Any ideas what causes this?)
If the checkout redirection fail, you should probably try to use the "Force a menu on the checkout" option via "Hikashop->System->Configuration->Checkout" to see if you'll be redirected to that menu