If they keep to the schedule, Kubica will be in a car during FP1 in Barcelona, but I guess it's mainly going to be to get a feeling of the upgrades with his own butt and relay that feeling to the engineers plus verifying sim accuracy, not to prepare setups for his younger comrades. Apart from that it's only sim for him in the near future. Heck, they said plain and simple, that during last test Kubica's priority was to gather info needed for comparison with sim data to make it more relevant. I hope they don't want Kubica now to virtualy also do what SS and LS should be doing in a real car by themselves (set the car for them).
Robert has been doing sim development for Mercedes in 2013 -2014, while he was working on their 2014 contender and it turned out good, obviously. I'm afraid though, that Williams is not as capable as Mercedes in most aspects, so I don't exactly expect them to suddenly win the WCC
Robert sure should still be a valuable asset in development and problem solving area, but troubleshooting, accurate feedback and most of all circuit setup is a race driver's job and it's vital that they do their job properly for other departments work as they should.
This was only the first race. Let's not write whole season off and call Paddy uncompetent because of a slow start. I won't say I agree with certain Williams decisions, as You have probably noticed by now, but still it's too early for definite judgment.