Hi,
1. Yes, you can edit the order confirmation email via the menu System>Emails of HikaShop. I don't know what is the email "welcome email on customer subscription emails" as there is no subscription system by default in HikaShop so I can't answer to that.
If you're talking about the akeeba subscription email, you need to see that with akeeba subscriptions.
If you're talking about the acymailing subscription email, you need to see that with acymailing.
2. Yes via the System>Emails menu of HikaShop as explained on point 1. Note that the order confirmation email is called "order status notification".