No. iPhones only support CarPlay. There is no HiCar client for iOS.
Officially, no. HiCar (like Android Auto) blocks video apps while driving for safety. Unofficial mods exist, but they require rooting and installing a patched HiCar APK that bypasses the "driving restriction." Conclusion: Should You Download the Huawei HiCar APK? If you own a Huawei phone: Do not bother manually downloading an APK. Your phone already has HiCar. Just go to Settings > More connections > HiCar and plug it into a compatible car. Use AppGallery only for updates.
If you have searched for the term you are likely one of two types of users. Either you own a Huawei smartphone (or a non-Huawei Android phone) and want to project apps onto your car’s infotainment screen, or you have a car head unit that supports HiCar but lacks the necessary software files.