One click unsubscribe, but asking the user if sure before commiting

There are several things you can do:

First. Unsubscribe link is a mandatory link. You cannot eliminate it but you can hide it. This is one of the options:

<span style="display:none;"><a href="%%unsub_center_url%%"></a></span>

Second Use the subscriber ID and email address in the email template you generate. You can use them in the AMPscript part of the email html. You can use them to build a URL to the new page.

%%[SET @clientkey = [_subscriberkey] ]%%
%%[SET @clientemail = [emailaddr] ]%%
%%[SET @clientkeyencoded = URLencode(@clientkey,1,1) ]%%
%%[SET @clientemailencoded = URLencode(@clientemail,1,1) ]%%
%%[SET @URLunsubscribe = Concat("www.something.com/?firstparameter=",@clientkeyencoded,"&secondparameter="@clientemailencoded")

Once you have built the URL you can use it like this in the HTML of the email template. href="%%=v(@URLunsubscribe)=%%

It is more than advisable to encrypt the parameters in the URL, you should not be comfortable having sensitive or personal data in the URL. You have some encrypt/decrypt functions in AMPscript but you could also use Javascript.

Is the resubscribe landing page a custom page for this publication? If so, you can hard code the publication list id into the the code to target the publication list you would like to re-subscribe the user to. I have used the code below for something similar:

SET @ll_sub = CreateObject("Subscriber")
SetObjectProperty(@ll_sub, "EmailAddress", @emailaddr)
SetObjectProperty(@ll_sub, "SubscriberKey", @process_subkey)


set @subscription = CreateObject("SubscriberList")
//process_listid from your original email
SetObjectProperty( @subscription, "ID",19121361)
SetObjectProperty( @subscription, "IDSpecified", "true" )
SetObjectProperty( @subscription, "Status", "Active" )
SetObjectProperty( @subscription, "StatusSpecified", "true" )
AddObjectArrayItem( @ll_sub, "Lists", @subscription )

SET @ll_statusCode = InvokeUpdate(@ll_sub, @ll_statusMsg, @errorCode)

IF @ll_statusCode != "OK" THEN
    RaiseError(@ll_statusMsg, 0, @ll_statusCode, @errorCode)
ENDIF

If the landing page is used for many publication lists you can pass the list id property value from the original email and then to the re-subscribe landing page when the button is clicked. You can declare the ID as a variable and use it in the SetObjectProperty. I have no idea how to pass a property from the original email off the top of my head but I know it is possible.