RE: Reduce $900 millions liabilities without MTN i Your scenario doesn't work.
Yellow Media can convert Preferred A and B into common shares at a common share price of $2 per share (so each $25 preferred share with some unpaid dividends will turn into a bit more than 12.5 common shares). They will almost certainly do this.
Yellow Media can't convert Perferred C and D into common shares except in a process like CBCA or CCAA. There is no provision for conversion to common shares.
Yellow Media can convert the debentures into common shares but only at the current market price. So $184 million of debentures would turn into 3 billion new common shares. Your plan would give up 85% of the equity and eliminate hardly any debt!
Yellow Media can't use its cash to buy back the 2013 and 2014 MTNs because of restrictions in its agreement with the banks. If YLO are meeting their secret revenue targets (a very big if), they can buy back some 2013s after they pay back some money to the banks. If they arent' meeting those revenue targets, they can't spend a cent buying back MTNs until either they pay back the banks in full or they get permission from the banks.