RE:RE:RE:RE:RE:RE:ENS goes from scary to a bargoon in two daysct....couple of great questions...
Obscure may have more to say on this topic.
In regards to the ENS preferreds vs the Commons, they really two very separate animals. There is no particular reason for them to trade in unison.
Essentially the dividends in the preferreds are guaranteed and are paid out of the income from the dividends received by ENS. The dividends on the commons are paid out of what is left (if any, from the dividends received after the prefs are paid) and capital gains. So in essence a portion fo the dividends paid on the commons is a return of capital. There is a risk with the commons that they won't pay out a dividend if the NAV on the units (commons plus prefs falls below $15 or generally under 5 for the commons). In the case of ENS this is a relatively minor risk compared some other split share companies.
As a general rule, the prefs trade around their NAV which stays relatively constant around $10 for a number of reasons and it best to read the prospectus to gain a more fuller understanding about this.
Your question about options trading and expiry dates deal with a very complex area which is by and large the domain of very sophisticated investors. Regular folks who decide to trade in options generally lose money and get taken to the cleaners by the pros (most stats over the years suggest that that number is about 80%). What happens at expiry date on options has a lot to do with with the number of options at different strike prices relative to the price at/near the expiry date...the type of options...and the hedging strategy of the pros (ie combinations of options {puts vs calls} and whether they are also long or short the underlying security. Don't know what the numbers are any more but "back in the day" about 70% of the daily trades on the NYSE were originated at the CBOE as options traders used a combo of options trades and stock trades to lock in a profit.
In simple terms, with all these factors in play, what happens on options expiry day is not a reliable indicator of what is going to happen in the future.