This is an accepted solution.
The online tipping feature will be available on your current plan as long as you have a functional checkout, however the tips will be subject to credit card rates. You can read more about this here.
Regarding Shop Pay installments, an additional fee will be deducted from your payout when a customer pays using installments. We're still figuring out what exactly that will look like, so we wouldn't be able to share specifics just yet. I'd suggest signing up for the waitlist here, as more details will be shared with merchants as it becomes available. Thanks!