From your lips to God’s ear.
I believe it is God's will that the chair of Peter be not vacant. Because of this, Benedict will live only so long as Francis exercises the petrine office. So, Benedict will die during or shortly after Francis' funeral making for an unambiguous interregnum.
In a surprising turn of events reminiscent of Benedict's own election, the conclave that follows will elect Raymond Cardinal Burke pope as I suspect many cardinals will see Burke as having suffered the stripes for the faith and will vote accordingly.
(God is keeping Benedict among the living until a sufficient number of the Saint Gallen "mafia" and their sympathizers go the way of all flesh so there will not be a repeat of their illegal maneuvering.)
If this is not what transpires my faith will not be shaken. God's will be done--not Oratam's.