Sorry but this would be an unmitigated disaster. Nobody watches 10 on Fridays, and the 6pm game would be slaughtered by the well established 6pm News services on 7 and 9.
Nobody watches 10 on Fridays because there's nothing interesting on currently. There's no reason why the viewers who watch NRL on 9 at 8pm on Fridays simply won't switch over to 10 and do the exact same thing.
For what it's worth, we already have a 6pm game on Foxtel going up again 7 & 9 news every week. 10 usually rates 100-250k in the 6pm-8pm block depending on what's on. It's on par with what 6pm game on Foxtel already rates and that would only increase on FTA.
You're also acting like the audience 7 & 9 News is 100% the same for the NRL. Between 6-7pm there are about 2 million people watching either 7 or 9 news. That means 25 million Australians are doing something else.
I hate to break it to you but go have a look at the 7 & 9 News demo breakdowns. 70% of the audience is over 60 years old. A lot of those switch off FTA after 7 or A Current Affair anyway.