Booking a Classic Room was possibly a mistake. LeGrand seems to stick to the "2 level upgrade" policy, so you will probably get a Deluxe at best unless they are quiet. The Deluxe Rooms are not massive, as you can tell from the description online (30 square metres?).

Last week I booked a Deluxe and got a Junior Suite, confirmed online within 2 days. My next booking is also a Deluxe and is so far only upgraded to an Executive Room.

Club access is guaranteed. You are unlikely to get a JS as I said, but if you want to ask for Room 4126, which has the best opera house view, then give it a go!

There are 2 desks in the lobby but they can be unmanned. If so, however, I would use the main desk unless there is a queue as dragging your stuff up to the lounge is not necessarily worth the effort, especially as your room will be on a different floor anyway.

Not sure why you've booked Luxury Weekends unless you want a breakfast downstairs, as you'll get the lounge breakfast for free anyway, and the 4pm check-out is also yours anyway. You may want to rethink the rate you book, depending on how much extra it is over the standard rate.