1) CSS Form Builder includes validation tools for both client and server side validation. to make some fields required, you would need to use the validation features of CSS Form Builder. Go to Insert -> WebAssist -> CSS Form builder -> Server Validation to start the server validation wizard.
2) security Assist manages the logged in state by using Session Variables. If you have Coolkies Toolkit installed when you run the SecurityAssist wizard, it will create a logout page for you automatically. To create one after the fact, you need to apply the Cookies Toolkit Clear Session Values server behavior. On you logout page, open the server behabviors panel, click the plus button and select WA Cookies Toolkit -> Clear Session Values. Set the event toi before page load.