when i brought my wife here in doha, she was not required to obtain return ticket... the only documents that were shown at the airport were the ones you just mentioned (passport with visa stamped from qatar embassy manila thru DHL)..only thing is that i was with her at the time of her departure from manila..and i was the one to show all the required documents.

maybe in your case since you will be coming here alone by yourself, (am not sure) you may be required to show a copy of the valid RP of your husband and letter of support but i believe it won't be required as you are coming here on family visa and not on visit visa only.

hope this will help you. good luck.