what are the chances that my family will get visitor visa??
Remember:
Visitor visa has its own intention and qualifications:
To meet, Business, Pleasure, seminar, Conference, tourism etc are purpose of Visitor Visa.
To get this you must demonstrate yourself "well to do" and solid ties to your home country.
"Solid ties" means well convincing reason of yours to remain in home country and come back after visa expiration abroad. These reasons are Job, Business, Family members, Property etc in your home country.
If you meet all those requirement, you will definitely get visa.
Although, everything is subject to the discretion of consular Officer abroad but if you meet the requirement you always get visa.