There is a forms portal component that will allow you to set search parameters to display Adaptive Forms and XDP forms.  AEM 6.3 Forms Help | Creating a forms portal page

Patches for AEM are found on packageshare, JEE patches are made available through support.  Enter a support request for JEE patches

Put a script on the button to validate that the required fields are filled.  You may need two buttons, one that the user sees and clicks on and once the validations are done it executes the click of the submit buttons.

I don't understand what you're trying to do.  Is this a form created in Designer or Acrobat?  If you're trying to combine the two PDF files this can be done in Acrobat.

AEM 6.3 Forms Help | Embed adaptive form in external web page

If you connect to http://localhost:port/lc do you see the AEM login page?  If so log in with admin/admin

Can you connect to localhost:port/adminui?  If so refer to Adobe Experience Manager Help | Preventing CSRF attacks

It's likely that you haven't whitelisted the machine you're trying to access the server from.  If you have access to the server launch a browser on the server and you should be able to get access to the url.  Your other option is to go to adminui and whitelist the machine you want to access or NOT R...

You're attempting to created an interactive XFA based PDF form.  Are you going to be trying to load this in a browser?  If so you'll run into issues, you may want to look at rendering the form as HTML5 or using Adaptive Forms.  Let me know which direction you want to go.

Can you try 1.8.0_112?  I seem to remember an update being pushed to my machine and it think it was that version and had similar issues.  Before you do that also check to ensure all bundles have started.