I think you've already made your decision on what to do, but better late than never here's my opinion. ;)

I think that intermittent fasting the way you plan it would be more like an extended long term fast. You would never fully stop being in ketosis but may not ever achieve the lowered metabolism and settling in for the long haul that is supposed to come after ten days... It would be interesting to see how it all worked. I would imagine that your eating two days per week would not quite keep you 'topped up' on nutrients and eventually you would during one set of five days fasting use up all your reserves and need to then fully Recover from the fasting.

At any time if you restart a fast within 7 days of finishing one, then ketosis will take hold quicker and whatever processes which had begun will continue on in spite of the interruption. Longer than seven days and apparently you are starting again from scratch. I think we could easily ingest enough in one day to survive for two as a rule without overeating. Maybe even eat one day and survive for three long term, but more likely somewhere in between one day eating, one to two days fasting. I think 5 days fasting and only two days eating would be stretching things a bit. But that's only long term, it would depend how long you planned to keep it up.

Andrew.