What happens if one of the four seeds who have a bye to the next round withdraw?
If they withdraw before the start I'm assuming they reshuffle the seeds (with Cirstea, then Boulter moving into the seeded positions, but if the tournament has started, do LLs get a bye? Or do the R1 winners sail through to the 3rd round?
My interpretation of the rulebook. If the schedule of play for the first day has been released and play hasn't started then the seeds are reshuffled as you say. If play has commenced on the first match then a LL takes the spot. If it is later than that I presume a walkover is given.
A lucky loser can replace a seed with a bye until the moment the players are due to walk on court.
Being a LL with a bye into round 2 is luckiest of all lucky losing.