1) You can purchase the CC teams for single app and you can activate the license on 2 machines but you can use only 1 at a time.
2) Synchronisation is possible with the CC licenses. You can save a file over the cloud and then share it with anyone you wish to.
3) What do you mean by decrease file revision?
4) Someone who does not have a subscription can only use a trial version which has very limited features and is valid only for 30 days.
5) If you purchase the full Adobe CC for teams, you can install as many apps as you want on the no.of PCs but only 2 can be activated at a time.
For further queries, Contact Customer Care
ad 3) I mean disk space in cloud. If i have e.g. 1 PSD with size 20MB and with 3 revisions in cloud. Does it take 60MB in cloud or 20MB?
If it is the same file, you can replace it or else it will keep on saving the copies of the same.
Moreover, you can change the filename to avoid confusions.