(Dev of WidgetLocker here
)
The truth is there is nothing simple about the lock screen from a development perspective. As implemented by the system it has very low level interactions, like handling buttons or how it's activated or how it interacts with other apps. The way most (all Market ones available I believe) lock screen modifications work is that they have an app that runs and either disables or suppresses the system's lock screen. There are some less invasive ways that could be done, but they'd be pretty limited (No volume buttons for example).
So a very simply implemented lock screen replacement isn't going to interact with the system well. Instead what you're looking for is a robust lock screen replacement that's been tested and developed for all kinds of system interactions. And that's WidgetLocker.
- secure
Widgetlocker respects the system's pattern/pin/password security
- Unlock with widgets
This is optional. You can have all widgets non-interactive, or you can have select widgets non-interactive, or you don't need to place any widgets at all. And you can put apps you want in custom sliders so you still have quick access to them but don't activate them by mistake. And none of these will bypass any security your phone is configured for.
- 2 lockscreens
This is a little hard to address as it depends on your security and your phone type. Assuming you're currently using PIN/Password you already have two lock screens, and for pattern you may also. I'm going to assume you mean you only want 1 slide to unlock screen and 1 security screen. In that case WL handles this perfectly on HTC Sense or the pattern lock on stock Android. Motorola android is more complicated, PIN/Password always require the moto-swipe, and pattern is a bit temperamental in that sometimes it wants it's own and sometimes it doesn't, working on this and should have it more reliable soon.
- Other apps
I've worked with several developers to get things to work well that normally wouldn't, either because of a lock screen replacement in general, or something specific on either of our ends. ClutchPad (in progress), Screebl Pro, Beautiful Widgets (animations), Fancy Widget (animations), ICE by Serra-Apps to name a few. Biggest known issues in this regard right now is with music apps that also try to replace the lock screen. This is something I plan on working out in the future.
Try it and if you don't like it you can refund it. If it's after Google's 15 minute period shoot me an email (kevin@teslacoilsw.com). As long as you're polite and let me know why you decided to uninstall, I won't have a problem refunding.