I like CREATIONS as well.
Lots of potential typography and word play opportunities
CREA M
CR EAT
CREAT E
ON
Which you can use in your menu.
It's already used by Cadbury for similar reasons:
https://www.cadbury.co.uk/products/Jelly-Popping-Candy-Shells-3760?p=3760
Pud as suggested already can work.
Mr. Pud
Mr. Waffle
Mr. Tazz
Cookies 'n Cream
Cookie Jar
Shake 'n Cake - can work with the American theme, and echoes Shake'n Bake
Tea and Cake, and Coffee & Cake could work as well, if you're going to provide either of those.
It seems to me that Shake shops are on the decline now (they were quite popular before), and tea and cupcakes are more in vogue (although the cupcake craze may well be declining now as well - giving way to cronuts and the like).
Coffee consumption and the popularity of coffee shops doesn't seem to be waning.
Creperies, gelataries, waffle shops, cupcake shops and even muffin shops can do quite well, especially in London.
A treat shop can do quite well as an alternative to bars for socialising and dates as mentioned, and as an affordable luxury making them quite resilient during harder economic times (coffee shops did well during the recession I believe)
Savoury can work fine, especially if you're going for the American theme (think crispy bacon and mapple sryup pancakes), however it can overcomplicate things and also adds logistical challenges - e.g. dealing with meat and foods that spoil and need to be handled separately and appropriately.
I'd definitely recommend serving coffee, and perhaps integrating it well too - e.g. Afogatos, Frappes, etc.
Healther options such as Frozen yoghurt and fresh fruit, which can be used in place of ice cream as well might be a good idea.
The concept made me think of a bright and clean cafe, with a large bar with fruit and deserts on display, and intimate seating. A walk in date spot etc.
That can work in a modern style, or more
Laduree style, which is popular in East Asia and with East Asian's in the UK I'd say.
Not so sure about American diner to be honest.
If targeting women, basing it in London or a city with a decent proportion of East Asians I'd probably be more inclined for a Laduree style, but then a refined American Diner style may make you stand out, as I only really know of Ed's Easy Diner and similar which are anything but refined.
Do make sure you get a website, secure a domain name (you may need to add online or something else to the end of the name), and build up a social media presence, as I imagine that will be invaluable for engaging with your typical clientèle. Think istagramed deserts etc.
If you have any questions on the website and hosting side of things then feel free to get in touch, we'd be happy to help.
I hope that helps.
Best of luck,
Dan