How to record input from multiple microphones so there is no latency between microphones due to writing to memory
The problem you're imagining doesn't exist, unless you create it. If you use a PC with a sound card with a multi-channel input, you will get frames of data where the samples from each channel are aligned. If you use a microcontroller, you can do the same thing yourself, provided the chip has enough ADC channels, and you can start the conversion on all of them at once (or close enough as doesn't matter). Other than responsiveness, it doesn't matter what order you copy the data in, or how long it takes to process; it only matters that all of the samples with the same index were sampled at the same time.