Right now the amount of money you pay to Jenny doesn't matter. DC has indeed rejected to add a foursome with them and made that even clearer by changing Jenny back to Debbie's daughter in the last update, which means now it's even impossible by patreon's standards.
If we think about the same thing, it'll open the possibilitly to meet a certain secret character.
For now that would be the case. She'll get a rework eventually though, where the outcomes will be different.
Here's a list for you:
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Basically every female character is supposed to get pregnancy content at some point - Mrs. Smith will get her's somewhat soon in "0.22", while Angelica isn't scheduled at the moment.