Yes, Levy has definitely upgraded quite a few features and finishes during the build. Not ideal, of course, but while it will certainly have added plenty to the cost and a little to the overrun, that's not the main reason for the delay. Most of the changes were implemented or decided long before the announcement back in August about the wiring issues.
As to the tarmac to paving claim, that's simply a matter of timing. Nothing to do with meddling by Levy. Had the stadium opened on time, there would have been a temporary tarmac finish to the stadium's immediate surroundings because there would have been no time to lay the paving. But since the opening has been delayed, it was decided that there was time to press on with the permanent paving finish to the public realm around the stadium.