Laptop recommendations?

I think 512 GB would be plenty for all three games plus TS4, and that includes as much store and custom content as TS3 can load without completely bogging down. I've heard of TS4 players with literally 70 GB cc, which sounds like it shouldn't be possible, but even that would fit. Planet Zoo's requirements list 16 GB free, and TS2 doesn't take up much space, so yes, your games should be fine.

If you have other large collections of data (music, movies, photos) though, you might want the extra storage. On the other hand, those kinds of files can be stored on and accessed from an external hard drive or USB without any noticeable impact on performance. So you could always get an external drive later if you need it for data, and leave all the applications on the internal SSD where they'll run much faster.

I hope you like it. Either way, it should be a really good laptop for what you want. And I can totally understand picking out a laptop, then wanting it right now instead of having to wait.