WP Users or Other? User specific order forms

What I’m aiming to do is to create an online order form website, where visitors must login to access it, and quite simply, it shows a form for the users to fill-in and submit. However, each form needs to be different, depending on the user, and the other forms hidden.

I’m pretty happy that I could use gravity forms for creating all the different forms, but i am not sure how to go about the user side of things.

1. Should I use normal WP users/registration/login, and then redirect them to a page that should display their custom forms, or is better to use another plugin, something like membership?

2. The website will be a standalone ordering website, so the home page can just be the login page. Should I just create a normal front page, and only add a login widget?

3. Are there any other tips and tricks that might be able to help me?

Best regards, CB