My opinion on your queries are as under:
1. Can she stay with me without losing her Chinese citizenship (she doesn't want to lose it & I respect that)?
Opinion: yes, it may be possible, being a wife of Indian she can stay in India without losing her citizenships of China.
2. Can she take up job in India with her Chinese citizenship (she is not professionally qualified - just an under-graduate) any legal procedure to follow?
Opinion: it may be possible that she get any job as per her profile but can not get govt. Services.
3. How often can she visit her family if she comes on a tourist visa or what kind of visa she needs to apply?
Opinion: she may apply for dependent visa which will be beneficial after the marriage.
4. As an alternative, if she takes up Indian citizenship, how to do it? Can she visit back her family? How often?
Opinion: as per section 5 of Indian citizenship act
Persons who are married to a citizen of India and who are ordinarily resident in India for SEVEN YEARS can be apply for citizenship by making application under section 5(1)(c). Application shall be made in Form-II.
There was a news regardingvthe same which is also mention as below.
new proposal is that the law be suitably amended to allow for a foreigner to be allowed breaks for a total period not exceeding 30 days during the prescribed period of one year stay in India before he or she can make an application for Indian citizenship. Foreign nationals marrying Indians presently cannot leave India even for a single day in the one-year prescribed period before applying for Indian citizenship.
"Representations have been received about the difficulties in fulfilling the criteria of one year's continuous stay in India before making an application on the ground that due to increased globalisation, there is imperative need for people to visit abroad due to economic, social or medical needs. The stipulation of one year continuous stay also causes genuine hardship in some personal situations where personal travel abroad has an unavoidable/inevitable context and in the case of skilled professionals on account of professional commitments," says a proposal of the Home Ministry made public now.
The rules so far stipulate a requirement of one year continuous stay before making an application for Indian citizenship in case of grounds of marriage to an Indian citizen, a foreigner who qualifies for naturalisation, an Overseas Citizen of India (OCI) Card holder for five years or any erstwhile citizen of India. The new rules will allow a foreign citizen to make multiple trips abroad in the stipulated period of one year provided the person is not absent from India for over 30 days in all.
The proposed change in rules will also allow minors, whose parents are Indian citizens of one parent is an Indian citizen, to be allowed grant of OCI registration. "Such minors should have the first claim for the grant of OCI registration as their parent(s) have still retained their Indian citizenship," the proposed rules say, adding that lot of representations have been received from the Indian diaspora and Indian Missions and Posts abroad regarding the anomaly where such category of minors are not considered for OCI registration.
The Home Ministry is also moving towards merging the OCI and the PIO Card scheme, as announced by Prime Minister Narendra Modi in USA last month. 2014.
5. Based on her getting citizenship, can she take up job like any other Indian?
Opinion: yes, she can.