Esoteric Makeup wrote:
...doing a super clean, skincare commercial worthy "no makeup" look.

Esoteric really don't know where to start here... Are you limited to traditional application technique or have you transitioned to more versatile airbrush technologies? 

Guessing the former simply select the leading women's magazines and carefully study skincare product advertisements... they will all have a somewhat universal aura... that is your mission to accomplish... 

That said since this is for social media you may have more latitude... one thing that is a given is you need to allow the talent's natural skin tone/texture and most certainly freckles to shine through... with traditional I'll use RCMA thinned appropriately and blended diligently with a sponge... it's all about precision with foundation application... Bridal artist are well versed at clean beauty and in reality it is by far the most demanding look to achieve... if your skill set isn't tops it will indeed show...

Rather than give examples of bridal here is a headshot in which the narrative called for clean beauty albeit the Kohl liner and gold accent was added to complement her amber iris... notice how her freckles shine through...

Here is an example of airbrushed clean beauty... however once again the eye decor is a bit much but you get the idea...

While not in your camp probably the most important aspect of a commercial skin care shoot is casting for the most appropriate talent (a porcelain doll here)... makeup is secondary to the aforementioned... skin needs to be like glass having a texture smooth as skin... the rest is rather straight forward... given the wrong talent no amount of tenure/skill/artistry will achieve the narrative...

Hope this helps...