Concrete landscape curb for dry-laid bluestone patio

We're putting in a dry-laid bluestone patio with a walkway. The whole thing will be edged by a brick soldier border, laid on top of the concrete curb that you can see already poured in the first photo here (second photo shows them laying out the forms).

A few questions (which I will also attempt to post in the super unfriendly r/concrete; they generally don't allow homeowners to post):

1a. Was the concrete curb installed correctly? I don't know what the standards are for landscaping curbs, but based on my amateur knowledge of concrete foundations in general, I'm wondering about the following: They didn't compact the dirt under it or add any base. There's no reinforcement inside the curb. There are no control joints. The curb was not poured in a single day, so some fresh concrete (hand-mixed, btw) was poured right next to concrete that was a day old. There are signs of surface cracks already at one of the spots where new concrete was poured next to day-old concrete.

1b. If it wasn't installed correctly, how big of a deal is this? Like, do we tear it out and redo, or do we forge ahead? For context, we're in North Texas…we get a solid freeze here about once a year, and the soil is annoyingly expansive.

1. The project lead initially told me (via text) that they couldn't pour the concrete until the brick selection was made. I was working from home the day he texted that, watching out the window as his crew was pouring concrete. I texted him, "They're already pouring, FYI." He responded, "The bottom of the concrete yes, but the top layer to mix in the brick to is what I meant." Now…based on my very slim knowledge of concrete, I thought it doesn't work to pour concrete on top of concrete. Is he just saying they'll mortar the bricks to the dried concrete?

Thanks for any insights.