Hey team, I'm building a cab booking application for my company. The concept mockup idea of the application is attached below.

While developing this application, I'm finding problem with

1) Using custom button inside the form

2) If custom button can be used with only pages, than how can we hide/Show those buttons depending on the current time.

3) I can able to fetch the email id using ("Zoho.loginuser"), but I'm not able to display their name.

4) How I can make the boarding point drop down to a pre-default value, that is unique to each user.

Pls, help me to solve these problems, ASAP