I would like to have 2 nodes have the exact Y or X axis positions, but I do not know how.

If you don't get of what I am talking about, here is an example...

Like so?

does it also work with smooth nodes?

Sure - but depends on what you´re expecting - if you want to maintain the curvature you might be better with rotating in object mode (S) or node mode (N):

I am expecting curves of the node but also expecting that both nodes have the same curvature

So it´s up to you what you prefer:

1. Original

2. rotated; length and curvature maintained

3. align+distribute; same width, line shortened, handle angles maintained

I guess 2 would maintain the curvature of the 2 nodes, am I right?

Also how'd I do the follow 3 curves of paths?, the steps for it