I used to do a lot more heavy vignetting (usually in Photoshop, later switched to using Lightroom for my vignettes) and yes, some photos a darker vignette looks great on. It tends to set the photo apart from anything else. I’ve found more in portraits though to lessen the use of it, mainly because if the client wants to order a print, the edges may be cropped depending on the aspect ratio and part of the vignette will be lost and part will be left behind. Though, if you’re the one ordering the prints for your clients you can make separate files for each print dimension and add the vignette as the last step. In Lightroom I used to put my vignettes to around 20-30 but have started only pushing them to around 10-15 (assuming both our programs are referring to a percentage).
Your recent shoot shows A LOT of emotion, which is what will set you apart, as long as you are consistently doing well technically. I love engagement and couple sessions, because the clients I’ve had have always made it easy to capture their love.
You have it easy if you want to change the name to your full name- I think Emma H Photography would sound just fine, and that way you can use it both now and after you’re married since the initial is the same letter.