Please define "call in another page". You can use Application.Navigate() to navigate to another web page. There is the multiforms demo if you refer to showing different forms.
2. I cannot see an issue with TWebTimer and there are no known issues with it. Test: drop a TWebTimer & TWebLabel on the form and add code:
procedure TForm1.WebTimer1Timer(Sender: TObject);
begin
weblabel1.Caption := timetostr(now);
end;
and this shows the running clock.
3. Please define "does not work"? There are no known issues. The demo TMS Web Project shows the use of a TWebHTTPRequest to retrieve JSON data and I cannot see a problem.
Application.Navigate(url, ntPage) if you want the page to appear in the same browser window.
I cannot see what exactly is going wrong for you with a TWebTimer. There are no known issues with this component. If somehow a problem persists, please provide a sample source project + detailed steps with which we can reproduce the problem here.