1- Technically 23:00 is just the most common time after the final prayer, the exact time is supposed to be after the final prayer in Islam it’s Al Isha’a, which is around 21-22:30 
2- Yes write as you please, so long as it is around in a circle it can be irregular, does not have to be exact. Go with your guts
3- Yes indeed
4- Mirhash: مرهاش, Al’ Hayash: الهياش, hope this helps