literally ""We see you after five o'clock"? would be "seni saat beşten sonra görürüz"
görüşmek (görüşürüz) is an "işteş/reciprocal" fiil in Turkish, so it just means the person who is talking, the person being talked to, will see each other. Therefore the subject is not "we".
Of course. There is rule in Turkish called vowel harmony which you can find about in tips and notes. And about ablative case... If you are going to use 'sonra' with a period you don't use anything other. But if you are going to use it with a point in time it should be used with ablative.
EX: Üç gün sonra görüşürüz. (See you three days later.) (period)<pre>
Saat 11'den sonra yatağa gidiyorum. (I am going to/will go to bed after 11.) (point) Gelecek haftadan sonra sınavım yok. (I don't have exams after next week.) (point, kinda) 5 ay sonra evleniyorlar.(They marry 5 months later.) (period) Mayıstan sonra okula gitmiyoruz.(We are not going to school after may.) (point,kinda)</pre>
Yes this sentence is a typical sentence. They can meet after five. If meeting before 5 is not possible and exact time is undetermined this is a typical usage. They can fix the exact time before meeting with a phone call etc. Also saying "around five" is possible: "(Saat) beş gibi görüşürüz."
Let's say it's morning right now and later you're getting off work at 5:00, and You're talking to your friend. you tell your friend that you'll come over after work, but you're not sure if you'll stay a little late at work or not. Your friend can say, "ok, see you after five"