A plugin that insert the standard login procedure into a page
Obviously no! I've tested it on some Apache and IIS Windows server... I'll be happy if someone will inform me about any problem.
I hope yes. The mechanics I use is (in theory) fully integrated with standard login, and so any plugin altering
wp-login.php can also alter InsiteLogin. I've tested with Register Plus and works very well.
I think it can work, but I've not tested... If someone can test, please report to me any inconvenience; I think this plugin can work with 2.3 versions, but I'm not sure.