On the ellipse guides it depends on how much are you willing to pay, one thing that i can say its to make sure they have markings for the minor axis and that they have a good range of ellipses degrees, the rest is up to you so you may wanna shop around.

There's complete ellipse sets (very expensive) or there is also an ellipse guide thats called pickett master that's called "master ellipse" i think that one is relatively cheap and its on amazon (its the one that Dab recommends, but there's also different options of the same brand).

One "warning" that i will say is that if you go with a "master ellipse" you will be limited in size and range of ellipses, so some things may or may not align, and depending on how big your ellipse guide is, it will obviously limit the size of your construction.

You may want to try Lesson 6 without an ellipse guide, some people succeed without one, some people don't, based on your work try to analyze what's best for you.

For the french curves im going to be honest with you, i don't think they are worth buying, because you will draw curves as straight lines, once you have a set of straight lines to define your curve you will then draw said curve (refer to lesson 6 page), so in my opinion you never really use a french curve because you already have good defined points to base your curve.