Dear friend
The most common cause for matting and hair loss is onset of hyperthyroid. They also exude a sticky substance from ntheir pores causing matting and a gunky feeling.
Here is a link for more information for hyperthyroidism in cats. http://www.veterinarypartner.com/Content.plx?P=A&C=&A=1197&SourceID=
I would have some bloodwork run with a T 4 test.
You can shave the mats with a mens battery operaed beard trimmer.
Of course stress may be a factor because cats HATE any change in their location.
Get a feliway plug-in at a pet store to calm all your kitties:
http://www.petplace.com/drug-library/feliway/page1.aspx
Please let me know how things are going.
Best of luck in your new home,
Terri
Feline Healthcare Expert
Expert in feline health and behavior. 20 years experience with cats.