Align lines with tips to waveform

Leo,

As I (mis)understand it, you can:

1) Use one of the shapes to create an Art Brush with a rounded end and a pointed end while having all but the rounded end stretchable (only needed if you use different lengths, unlike in your latest screenshot);

2) Create the lines as a Blend with the desired length(s)s as 1pt stroke/nofill paths with the suitable options (Align to Page if you with to have them vertical as in your latest screenshot (or at other angle)), Align to Path if you want them at a certain angle (such as perpendicular) relative to the path;

3) Create a curved path orresponding to the middle of the lines and Replace Spine, most likely you will need to Add Anchor Points a number of times to get an even Blend;

4) Expand the Blend and apply the Art Brush to all the lines.

You can see how here, for the Art Brush,

https://helpx.adobe.com/illustrator/using/brushes.html

And you can see how to do other things by similar searches here,

https://helpx.adobe.com/search-results.html?q=art+brush+illustrator&scope=%5B%22helpx%22%5D&subscope=%5B%5D&limit=10&start_index=0&sort_orderby=relevancy&sort_order=desc&post_facet_filters=%7B%22applicable_products%22%3A%5B%5D%7D

Edit: Here is a set of images showing the stages (Art Brush/line height 600pt, hence the thinness) corresponding to your latest screenshot:

Click/RightClick to see in full (and get closer), Click again to get closer (still)