My interpretation means nothing of the sort, read it again, the whole thing! Should the receiver choose to enter the line out legally before or after the ball is thrown then he is no longer the receiver but just another member of the line out and can do all the other things done by players in the line out. The point about entering towards the back of the line is that he will not have sufficient time to enter the line anywhere else after the ball has been thrown should he be part of a lifter/lifted combination; nobody is that quick.
Agreed.
I don't know where you got that idea from. Visualize the receiver standing 2 metres from the line abreast of #1 and #2 in the line out. Do you think that, taking his cue from when the ball leaves the thrower's hands, he can get in, jump and be supported in time to catch the ball? His only possibility, should he wish to do that, is at the tail end.
This doesn't need to be complicated.