Miyajima fireworks

We would like to get from Hiroshima to Miyajima to watch the fireworks on Aug 11. We think it will be very busy that evening.
Is there any way to reserve tickets in advance either on the boats /trains from Hiroshima to Miyajima and more importantly to return from Miyajima to Hiroshima AFTER the fireworks end at 2040 (all the accommodation on Miyajima were sold out months ago) ?
Will there be any special travel arrangements (such as extra trains or boats laid on) on Aug 11 in anticipation of the large numbers of travelers going to Miyajima to watch the fireworks ?
Would it correct to assume that the 2 ferry Companies from Miyajima Guchi to Miyajima Island do not allow advance reservations of their tickets, (and if so, we may have to stay on Miyajima Guchi to watch the fireworks from there) ?
Finally, is driving from Hiroshima to Miyajima Guchi an alternative (so as NOT to risk not being able to get on the trains to/from Miyajima) or will the traffic be really bad (we were thinking of driving from Hiroshima at about 1pm--will the traffic still be heavy at that time of day ?) and MORE IMPORTANTLY, will the car parks all be full up near the ferry (any suggestions for parking further away ?)

This japanese page talks about Miyajima firewarks.

http://itsukushima.ti-da.net/e3080158.html

I translated some important topics.
-There are extra boats of "Matudai Kisen"(boat company) and "JR"(railway company).
-The last departure of "Matudai Kisen" from Miyajima guchi is 23:00, and "JR" one is about 24:45.
-It takes 2 hours to go to the boarding point in the crowd.
-There is no one who can't take the last boat on fireworks day.
-If you want to go back Hiroshima avoiding the crowd, you should go off there at the start 10 minutes.
-If you go by car, you must arrive at Miyajima in the early morning to park a car.

It seems that there is not reserve tickets, but you can return to Hiroshima the same day.

Thanks a lot Kei. Re your comment below, do you mean to avoid the crowd we should board Miyajima island ferry 10 mins after the start of the fireworks or 10 mins before the end of the fireworks ??

-If you want to go back Hiroshima avoiding the crowd, you should go off there at the start 10 minutes

I mean you should boat 10 mins after the start of the fireworks.
This HP owner said "There are many people who back to boating point 30 mins after the start to the fireworks."

But if you don't mind to wait 2 hours for boating, you can watch all fireworks. And I recommend you enjoy all fireworks, since it was a rare opportunity.

Got it, thanks Kei.
Do you know if it is about the same if you watch the fireworks from the mainland ie: Miyajima Guchi ?

According to this sight, you can see fireworks from main land.
http://find-travel.jp/article/612

The speedboat racecourse "Miyajima Kyoteizyo" provides free space to look fireworks on Aug 11.

I put a link to "Miyazuma kyoteizyo".

https://www.google.com/maps/place/34%C2%B018'53.4%22N+132%C2%B018'20.9%22E/@34.31484,132.305813,17z/data=!3m1!4b1!4m2!3m1!1s0x0:0x0?hl=ja

Hi Kei,
Although we are not quite sure what you mean by :

The speedboat racecourse "Miyajima Kyoteizyo" provides free space to look fireworks on Aug 11.

We will see if they will allow us to walk out to the breakwater to watch the fireworks or not, probably not for safety reasons. Anyway, we want to thank you so much for all your help. Maybe we will try to reserve dinner in the hotel below near Miyajima Guchi and hope to watch from the hotel restaurant. Thanks again.

http://www.kankou.pref.hiroshima.jp/sys/data?page-id=2670
.