LeLagus Yes, you can move or copy your saves into the saves folder inside the new Sims 4 folder. Make sure you're placing the files directly inside saves, not in a subfolder.
As for your crash reports, I don't think the developers would be interested if these crashes happen only with your mods installed. If you get a crash log with no mods or custom content present, you can upload the log and your save (both are requested) and post the link in this thread:
Crashing | EA Forums - 13467034
The thread is only covering crashes that happen with no mods and cc and that aren't attributable to some kind of system issue, which is one reason we don't stuff all crashing posts into that.