OTF Font Personalization: Swashes, Glyphs

I would like to replicate this customization https://i.imgur.com/BmPObHU.png . My customers would have two text fields where they type the name. One with left word, and another with right word. The challenge here is the left swash, the heart, and the right swash.
After verifying the technical side of the product customization engine, I came to the conclusion of using 2 fonts derived from the same font. https://i.imgur.com/oLCjWJ6.png

Font 1 for the left word with:
-A very long swash attached to the first letter whether it is uppercase or lowercase
-The heart always attached to the last letter wheter it is uppsercase or lowercase

Font 2
- Left letter should always be attached to the heart like this https://i.imgur.com/xAfqZRI.png don't matter if it's attached to its top or middle or whatever
-A very long swash attached to the last letter whether it is uppercase or lowercase


Why a very long swash ? Because i don't know if someone will enter a short name like Lee, so if it's a short swash, it won't go until to the border of the heart, but a very long swash will always touch or go slightly over the border.
I've already got the font to be modified on