Last time of Isha and Tahajjud prayer

I recently saw an answer for the last time of isha prayer and it says it's until fazr begins. It also says it is makruh(disliked act) to pray after midnight. Then i saw last time for tahajjud prayer and benefits of that and came to know the best time is the last 1/7th of the whole night. **Now how can i do that as according to another information we should pray witr after tahajjud.** *Isn't my witr would be makruh(disliked act)!!* Please shed some light in context of Hadith and Quran.