My listing is a guesthouse (tiny house), it is in my garden, and I have a pool that is not available for guests. No guest has ever asked to use the pool, and I’ve hosted over 80 stays.
My setup is a bit different though; the guesthouse is on one side of my house, the pool on the other, not visible from the guesthouse (but visible from the street). And I have set max 2 guests, so my guests are typically adults, not families with kids.
I think you’ll be fine, as long as you make sure the pool is not visible in any photos, you mention in your listing that there is a pool that it is not available, and maybe try to tailor your listing towards a target group that might not be that interested in the pool.
I’d be more worried about whether the children swimming/playing will disturb the guests…😉