Hi,
To have two terms and condition checkboxes, you need two "terms and conditions" views added to your checkout workflow. That was the case before too. So add a second one if you want a second checkbox.
Now I don't see why you get that error with the input field. I certainly don't on my end. Are you not able to remove the extra text added there ? I would need a backend access to your website to be able to check the situation directly to be able to tell you more.
There is no option to have the link as not a popup.
But it's possible if you change the code in show_block_terms.php via the menu Display>Views.
There, you can replace:
$text = $popupHelper->display(
$text,
'HIKASHOP_CHECKOUT_TERMS',
JRoute::_('index.php?option=com_hikashop&ctrl=checkout&task=termsandconditions&step='.$this->step.'&pos='.$this->module_position.'&tmpl=component'),
'shop_terms_and_cond',
(int)$this->options['popup_width'], (int)$this->options['popup_height'], '', '', 'link'
);
by:
$text = '<a href="'.JRoute::_('index.php?option=com_hikashop&ctrl=checkout&task=termsandconditions&step='.$this->step.'&pos='.$this->module_position).'" target="_blank">'.$text.'</a>';