Yes it is possible to get TRV while sponsorship file is in progress. My mother got the visitor visa and her file for immigration is in progress. Before applying we called CIC and they told that these are two different departments and immigration filing does not effect the decision for TRV, however in the visito visa file u shud show that u will be taking care of all their expenses, including food, stay etc.

also u can chk with some professional, like in Brampton we have brampton neighbourhood where lawyer will chk the file for u for free.