What issues is there with a 223 mags there are about 6 good choices . there are polish , bulgys, tapcos , weigers, galili etc all will work fine . You might need to widen the trunion a but but it can be done with as die grinder an a stone ot carbide . I use tapcos mags in my weiger clone an thye work fine . I also can run bulgy as is an galial mags with a dab of weld on the lug were it engages the trunion .I think I like the idea about the 5.56 but barrel and mags seem to be the issue with this route.
you want issues start adapting ar mags that are still being developed after 45 years . Yea ar mags are a couple mags less but how many nags do you need? If your worried about costs your only going to need tow or three . hell I got guns with only one mag .
sure AR mags are about $10 but you need a $150 or more addapter an then the mods to make it fit . an for what so you can scare zombies better? I dount any one is going to be doing a in combat mag swap an If you thing your fast with a ar set Up I can show you russian an Israeli videos of some lightning fast mag swaps
a 223 barrel is pretty simple to do in a ak 75 trunion buy on with not gas port turn it to fit the 22 mm trunion an press it in buy or modify what ever barrel parts you need an make them fit . There was a guy here making them to fit as is on a AK 47 kit .
This is not a AR 15 you actualy have to do some work to build a rifle in the AK world .
what exactly do you have in your possession for parts ?