It could be that the remaining targets on our list are only going to move later in the transfer window.
Players like O'Brien, who clearly aren't wanted at their current club but the club wants as much money as possible for them, or the player is waiting for a better contract offer. Or out of contract players who are holding out for a better offer from a club.
If we want a young PL player on loan, they usually don't happen until the clubs have finished their pre-season tours and decided which youngsters are going to be part of their first team squads and which aren't, freeing the latter up for loans.
There's also players who the club are aware will become available, but the selling club needs to buy a player first. Or we need to sell a player before being able to make the signing. The transfer market is often described as a set of dominoes waiting for the first one to fall and that does seem to be pretty accurate.
TL;DR - it wouldn't be a surprise if any other signings come towards the end of the transfer window.