I did some reading, and it seems possible to disable notifications of text messages by setting the priority of the app higher than the default SMS app. The only problem is that apps like GoSMSPro use the highest possible priority already. So if you have an app which does that, it is not possible to stop it from receiving the SMS, and if it sends a notification for every text message, it'll keep on doing that.
Did you submit an error report for the crashes? It should give you a "report" option on the force close dialog. The technical information the system includes in the report makes it A LOT easier to track down the error.
I haven't given much thought to the number thing. Having comolex expressions as responses is starting to get a little out of scope for the current version. With that said, once I'm happy that this is stable and has the minimum features for usability, I'll probably begin work on a Pro version.