How does one make up for missed prayers unintentionally, and does one renew ablution after making up each prayer?

You must make up missed prayers immediately, to the best of your ability, as long as it does not harm your body or essential livelihood. The Malikis permitted making up two days' worth of prayers with each day. You should make up the prayers in order, to avoid the scholarly disagreement regarding the obligation of sequential order. One ablution (wudu') after the time for prayer begins is sufficient for all prayers as long as you are afflicted with continuous discharge.