1 - True, a free() is missing when unregistering a RAYDIUM_REGISTER_ICONST or RAYDIUM_REGISTER_FCONST constant. Nice spot.
2 - I'm not sure to understand what you want to do with zip files, but here's the thing, in my opinon: yes, recursive calls to PHP leads to a segfault. Yes, as a workaround, it's possible to use zlib directly, but yes, it's quite sad to "duplicate" what PHP can already do (in facts, PHP interpreter is in Raydium because it's supposed to help for such things). To make it short, the "correct" path would be to dig a lot and find why we're not able to do recursive calls to PHP. Fixing this would allow a lot of excellent features. I'm thinking about this for ages, but never took the time so far