I have not been to PL for a couple of years but can answer most of your questions, and I doubt there have been many changes to the Gorillas there since, apart from the arrival of the Koulliou group from Howletts. They replace the ill-fated Djala group that was sent to Africa and reside in the Palace of the Apes.
Circular 'Loft' pavilion enclosure( now offshow). Contains five(?) adult males (originally more) 3 (Ambam, Djimu, Kush) still live together. Two( Mataki,Timbou) live separated as singletons due to fighting. Others that lived in here are Djanghou(now at Howletts), Boumi (died) and Oumbie( sent to Twycross) This circular enclosure can be partitioned into sections, like dividing a Pie, and was the first quarters specially built to house bachelor males at Port Lympne. Consequently it still has the oldest males. It connects with the lower of the two big outdoor areas.
Other standard-shaped 'Pavilion' enclosure. Contains 4 younger males, all sons of 'Kifu' at Howletts and came from his group. This connects with the 2nd, upper large outdoor enclosure.
Adjoining this is the Ex Chimp cage with the cylindrical tower outside. Sometimes empty. Has contained several different single adult males in the past(Djala, Jomie, Ujiji) and is used when necessary as a 'spare' enclosure. I've never seen the 4 males currently living next to it,being allowed to use it, but Gorillas given access to this certainly use it.
Palace of the Apes. The last major build for Gorillas at Port Lympne/either Park. Originally held the Djala group. After their return to Gabon, the large Kouillou group were moved over from Howletts. If it is currently split, it may be because some moves are afoot e.g. removing younger males or females from it. But the empty(?) enclosure at Howletts is I think likely to be earmarked for the new male 'Matadi' coming from Paignton shortly, plus several females, both homebred ones and a couple from Hanover Zoo, to form a new group.
Chimps- from memory they were kept on straw like the Gorillas.