I don't konw any of them in details, except Shah Wali Ullah r.a. You can read "Taqleed ki Shar'ee Hasiyat" by Mufti Taqi Usmani Sahab, in which he discussed, why the schcolar were inlcined to Quran, Hadith and retrospective study of rulings, instead of blindly following the "Fighi Mazhab".