Digital Products. Where are you selling to? If Europe, Yes. US, depending︀ on the states. You don't need advice from them here, just use quaderno or taxjar︁ to calculate. Or even beter, use Paddle.
As for Federal taxes, it depends on the︂ exact nature of the digital product, but generally no. There's a proposed regulation on digital︃ content in 2019, which clarify up a lot of things. If you pm me, i︄ will send you the notes. Although it has not yet been finalized, but it generally︅ meant that is the stance taken by IRS and Treasury.
Hiring US independent contractors, incidentally︆ i'm researching into this as well, but my inclination is no, would be better if︇ there's a tax treaty between US and the other country, but since you want to︈ do it in a offshore jurisdiction, so that's out of the question.
Bigger risks here︉ I see here though is Singapore.