jazakallah kair @qdinar .. i remember this hadees but i dono where it is present.. jazakallah kair i got it... edited my answer supported with hadeed

do you believe mihraj ? how much salah does allah obligate to us during mihraj? dont you think if witr is obligatory it will against mihraj? allah mandatory 5 times prayer . dont include witr in it. allah dont want to give burden to us. if you wish you can pray simply

nothing in that . its just about vitr. prohet said make it witr as last prayer of the night. beyond witr you shouldn't do anything else til fajr. you are not allowed to do even nafil. this is rules to restrict people

there is authentic hadith from buhari 46, then you why seek something else?

allah command us to follow prophet muhammed(sal) not based on our own desire to follow someone. so, if you follow someone you will be questioned during Qiyama and your leader will leave you on that time except mohammed (sal) .

Jazakallah kair. Will see and will modify my answer