e-ticket problem

I think it is OK.
For the flight, you are going to Taipei (TPE) at the morning. For KA & CX, you may have the seat reservation within 48 hours before the flight taken off.
Current, all the nearly all the airline use e-ticket rather than the original paper ticket.
The one you must have is the booking/confirmation number of the e-ticket. It shall be a set of number and letter for airline/agent booking and seat confirmation purpose. For all on-line, phone enquery, you may quote the reference number for checking.
Do you have the on-line Taiwan Visa? or you have prepare to have it when you arrive the Airport? Ensure you have the NT (New Taiwan Dollor) for the visa application at the counter.
For doing the application in HK, it only cost $55 (approximate) and can collect it at HK Int'l Airport. They have a counter in the airport for Visa handling (near H row - the last row in the chack in floor).
Don't worry and enjoy your trip.!

e-ticket 等同以前既機票但唔等於已經有機位, 由於所有航空公司都會 over-sold 機位, 所以一定要之前上網或當日預留時間出機場喺航空公司counter 出登機証。最好帶埋e-ticket check-in, 因為我見有d人淨係帶passport 唔帶e-ticket 去check-in, 以為電話已經有晒資料, 點知嗰日班機唔飛, 要既時轉航空公司要用人手出 broading pass, 出事啦。個客話 "我以為你地電腦有架嗎!" 最後係自己攞嚟煩! 我攬定自己嗰份, 唔知佢地最後上唔上到嗰班機。由其係回程時, 其他地區如大陸有d機場, 資料不全會問你攞e-ticket 對, 雖然有時出示咗都係無資料, 總好過無証無據。

check if there is the word "confirm" beside the flight detail on your e-ticket, if yes, that means the booking is confirmed.
You may also call the airline in Hong Kong to check the booking, giving the booking reference number shown on the e-ticket. You can also request the airline to reserve a seat for you, then the staff will tell the seat number.