You are allowed to disable Smart Actions (and many other things) just by going into the settings>apps menu and clicking on them. If it's a preinstalled app that you are allowed to turn off, you will see that the "Disable" button is lit up for it. Some apps you will click on, and Disable is not an option, meaning it would require root to freeze or remove them.
After being on .247 with custom, thinned-out ROMs, I just took the official .246 update, and I was able to get the stock ICS rom into decent condition without using Titanium Backup or anything else to remove apps. Most of the garbage that I wanted gone was able to be turned off in the apps menu.
As far as directly answering your question, a Google search brings up many lists of what is safe to freeze.
Freezeable ICS apps
The point of freezing, though, is that it technically still leaves the files there without fully uninstalling them. So you don't really need to ask ahead of time about whether it is safe or not, as freezing is never really "unsafe". Only fully uninstalling is dangerous. If you freeze something, and it creates a conflict, you just unfreeze it and put it back.