All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
First of all, may Allaah reward you for being keen on urging your wife and daughter to wear Hijab, and we ask Allaah to enable you to this effect and bless your family.
We will summarize our answer to your questions in the following points:
1- A man is responsible for his family and he should do what would rectify their worldly and religious matters, among which is the matter of Hijab. Allaah Says (what means): {O you who have believed, protect yourselves and your families from a Fire whose fuel is people and stones.}[Quran 66:6] Also, it is confirmed that the Prophet said: "…and the man is a guardian of his family and will be questioned about the people under his guardianship." [Al-Bukhari and Muslim]
2- Hijab is an obligation on the Muslim woman, and if she does not wear it, she is sinful and she deserves the Punishment of Allaah. Abu Hurayrah narrated that the Prophet said: “There are two types of people who will be punished in Hellfire and whom I have not seen: [the first type are] men who have flogs like the tails of cows and they beat people with them, and [the second type are] women who are dressed but appear to be naked who will be inclined (to evil) and make others incline (towards it). Their heads will appear like the humps of the Bukht camels inclined to one side. They will not enter Paradise and they will not smell its odour which is smelt from such and such a distance [from a great distance].” [Muslim] For more benefit, please refer to Fataawa 89972 and 84053. Moreover, any disobedience may have an effect on its doer or on some members of his family, as some pious scholars from among our righteous predecessors said: ‘‘I disobey Allaah and I consequently find the effect of that on the conduct of my riding animal and on my wife.’’
3- The fact that some women who wear Hijab do some prohibitions is not defamation for the Hijab, or a reason to seek excuse to abandon it. If this argument is acceptable, it would become permissible for everyone to abandon the prayer on the excuse that some people who perform the prayer commit some prohibitions like Zina (fornication or adultery), or consuming intoxicants, or dealing with Riba (interest and/or usury), and there is no doubt that this reasoning in wrong. For more benefit, please refer to Fataawa 90981, 90018 and 86492.
4- The (Islamic) Hijab should meet some conditions that we mentioned in Fataawa 84341 and 83702. Therefore, any clothes that fulfill these conditions are a proper Hijab, but in general the skirt that women wear today does not fulfill some of these conditions.
5- We advise your daughter to wear her Hijab as it is the symbol of a chaste woman and the source of her beauty, and it is a protection for her from the disgrace of this world and the punishment of the Hereafter. She should spend her youth in the obedience of Allaah so that she will be among the seven kinds of people whom Allaah would shade under His Shade on a Day when there would be no shade except His Shade (His Throne’s Shade). [Al-Bukhari and Muslim] For more benefit on the advantages of Hijab, please refer to Fataawa 88490 and 86341.
Allaah Knows best.