1. I am not sure if she will have problem in KSA. But, while entering Qatar, there is be no issues for female solo traveler.
2. Yes, it is mandatory to have a credit or debit card in her name. Else, she needs to carry 5000 QAR. Proof of fund is a must for on arrival visa.
3. Hotel booking is not mandatory. You can give copy of your Qatar id and address to your sister. At immigration, she has to tell your address when asked "where will you stay" and show your Qatar id. She can also tell that you are her brother. Alternatively, you can book dummy hotel room from booking.com.
One more thing you need to note is, she has to show her return ticket as well. Hope this helps.
1. I am not sure if she will have problem in KSA. But, while entering Qatar, there is be no issues for female solo traveler.
2. Yes, it is mandatory to have a credit or debit card in her name. Else, she needs to carry 5000 QAR. Proof of fund is a must for on arrival visa.
3. Hotel booking is not mandatory. You can give copy of your Qatar id and address to your sister. At immigration, she has to tell your address when asked "where will you stay" and show your Qatar id. She can also tell that you are her brother. Alternatively, you can book dummy hotel room from booking.com.
One more thing you need to note is, she has to show her return ticket as well. Hope this helps.