Yes. All the pages. If not using the default cmdLet you can also modify then using JavaScript. You can load your own JS code that will make that page looks like whatever you'd like.
Those type of customizations are explained here: Advanced Customization of AD FS Sign-in Pages.
You can use the developer tools of your browser, select the area you want to change. Spot its element ID like in there:
Then you can follow the procedure given in the document and change stuff. For example:
// Check whether the idp_SignInThisSiteStatusLabel element is present on this page.
var idp_SignInThisSiteStatusLabel = document.getElementById('idp_SignInThisSiteStatusLabel');
if (idp_SignInThisSiteStatusLabel)
{
// idp_SignInThisSiteStatusLabel element is present, modify its properties.
idp_SignInThisSiteStatusLabel.innerHTML = 'Blablablabla';
}