Yes, you can swap RAM between different companies.
Yes, you can swap RAM between different companies.
Yes, you can switch to another manufacturer for the remaining sticks and increase your RAM by adding two 8GB modules.
Take note that this should function in flex mode. https://www.intel.com/content/www/us/en/...-kits.html
To add: Even if they don't match, it may still work, but you'll drop down to the lowest common speed, highest timing etc. essentially paying for performance you're not getting in this situation. But you could also run into incompatibilities where it doesn't work unless you remove some of the sticks. When you buy RAM you should see something like 3200 MHz (the speed) and e.g. CL 16, that's the timing. The lower this number, the better. However, there's a dependency between frequency and CL (because it is measured in clock cycles), so e.g. 3200 CL16 and 3600 CL 18 actually has the same absolute latency in nanoseconds.
Generally, you only need to align speed. Timings: The voltage: It’s not essential to understand the exact values—what matters is consistency across all devices. You can use RAM with different specifications and still function, but it’s better to avoid troubleshooting if issues arise. Focus on matching those three factors. Size isn’t important for compatibility.