757 Speedbrakes
The 757's I believe were for expansion by Allegiant for new Hawaii routes and it was announced in March 2010 with great fanfare.
March 5, 2010: ALLEGIANT TRAVEL COMPANY TO PURCHASE SIX BOEING 757 AIRCRAFT Company Plans to Say "Aloha" to Hawaii | Travel Is Our Deal | Airfare & Hotel Packages from Allegiant
However several articles around November 2010 stated that the plan was
delayed until February 2012 due to ETOPS problems. Hence the aircraft were destined for Allegiant but they do not require them for over a year and hence the rumour Jet2 came in for them.
Allegiant's service to Hawaii pushed back to 2012 - Hawaii News - Staradvertiser.com
If the above link opens it explains the delay.
LBIA
A typo I think as KZC is a KLM F70, I believe HZC is the one, which is last shown on acarsd as flying on Christmas Day!!!
Random Flyer
Keep an eye on the CAA site G-INFO as this is pretty useful.
GINFO Database Search | Aircraft Register | Safety Regulation
Pete