That would be my preferred choice. or connect them all to a router.
If going for several ESP as a STA, you have to keep in mind that an ESP as an AP has a maximum of 8 devices connected, but you would be within that limit.
It is easy enough to set up, and you could just send tcp packets, or get the STA to POST on the webpage that the AP-ESP is hosting, and your app can read it from there. Or get the main AP to request the data by doing a GET request to pages the STA's are hosting.
I would just a router and the 2nd method.
That would mean your device has to connect to all ESP's individually, that takes time. A lot more time than visiting different pages.
tcp packets are obviously the fastest. Pages are really easy to debug.