Bastille Day and visiting Paris from DLP

[maleficent_mum]

Circumstances meant we had to postpone our March trip, it has been rebooked for July and means we are at DLP on Bastille Day - Sunday 14th July, now we we were planning 2 park days, then spending the weekend in Paris( travelling by train from DLP) and then 3 more park days.

Is this still realistic with the Bastille celebrations ? I understand the Louvre is free to visit on Bastille Day, do any other attractions do the same ?
We'd like to see the military parades, where would I find times and route ?

Naturally the Eiffel Tower is on our list but will that be open on the Saturday & Sunday or closed while they set up the fireworks display, I intend to prebook the tickets online but any recommendations for best times to visit?

And lastly if we stayed to watch the Paris fireworks how easy will it be to get back to DLP, or should we just head back to DLP and enjoy the fireworks there ? Is there ever anything on in the village, Billy Bob's maybe, to celebrate - my boys are 19 and 14 so no little ones to worry about.

I'd chosen Saturday and Sunday to visit Paris to avoid the chaotic Park, but we have 7 days so we can be pretty flexible.

Thanks in advance.  

PS Read somewhere that most shops close on Bastille day is that still the case ?