Advice on creating a B2C SaaS Marketing Plan?

Nice product and LP!
I have a feeling PH users will resonate well with the app, especially as many people are anxious these days.
My personal plan for B2C product launch plan would be the following:

• Who are your early users, have you talked to them beyond friends/family? Why do they use the product? What are common characteristics? Are you able to create a persona?
• Using the persona above, I would create an ideal marketing calendar that extends for two months. This is your ideal scenario, and tie each milestone with a KPI (i.e. user growth? usage growth? rev growth?)

More tactical below:

• Reflect on the launch plan to see which surface area you're covering, for example, if you were to post your product on PH make sure that you have the right messaging and product demo/images that resonate well ahead of time. Make sure that there's a clear CTA once new users land on your page! Conversion there is key. Finally, make sure your product can handle an influx of volume! Before I post on "you only have one chance to make an impression" channel like PH or even Reddit, I would test a bunch on free and low impact channels. That means I'm looking at Twitter, FB, LinkedIn - wherever your users are.
• You can try to give the product out to users with a network out as a good will thing. For example, would mom bloggers like the app? Perhaps! Find a list of 5 - 10 to start with and cold reach out.

It takes time but there's a lot of surface areas to tackle growth, I'm happy to give feedback on your plan. My email is in my profile.
Best of luck!