Unlike in past transfer windows, Everton have moved quickly and in a sure-footed manner to secure the targets that Sean Dyche and Kevin Thelwell have identified, and should they add O'Brien it would represent an already impressive window.
Going into the summer and after a campaign of such chaos and controversy - with two separate and unprecedented points deductions imposed for PSR breaches - it looked as though the Blues were in for a very tough and uncertain off-season.
Without a new owner - after 777 Partners long-running takeover bid collapsed at the end of May - and severe levels of debt, for a while there was even some media talk of a major 'fire-sale' of players to balance the books and prevent another possible breach.
Then came news that one of the other parties that had emerged and were interested in purchasing the Toffees after 777 Partner's withdrew, had entered into an exclusivity period with a strong chance of completing a takeover at last.
However, that party The Friedkin Group, decided against a deal after concerns about the complicated debt situation, leaving Everton back at square one yet again.
But despite all the upheaval and financial constraints that have surrounded the club, Dyche and Thelwell have added Jack Harrison back on loan for another season, Tim Iroegbunam and Iliman Ndiaye on permanent deals and then a few days ago Jesper Lindstrom also initially on loan.
While Iroegbunam probably represents one for the future, Harrison, Ndiaye and Lindstrom will surely come straight into the Blues starting eleven and strengthen it, particularly in attack where significant improvement is so needed.
Given his quality and experience, were O'Brien to sign, he would also be pushing hard for a place in that first-team as well.
In addition, the Blues have held firm over their star centre-back and England international Jarrad Branthwaite, successfully resisting Manchester United's repeated attempts to prose him away.
And although there is still plenty of time left in the window for things to change, it looks more likely that he will be staying at Goodison Park - for another year at least.
There has only been one major player exit that of Amadou Onana to Aston Villa, along with reserve forward Lewis Dobbin who also joined the Midlands club and defender Ben Godfrey.
Onana's £50 million departure had long been anticipated and was not either a surprise or a deal that has likely perturbed most Everton supporters.
The money raised by Onana, Dobbin and Godfrey's departures together with other income and Freidkin's further loans, has steadied the ship, hopefully prevented another PSR issue and given the Toffees enough wiggle room to conclude these deals.
Throughout all the wheeling and dealing, there has been a consistent theme with the Blues looking for younger players who certainly have something to prove.
So, overall it has been a strong, smart transfer window so far and there is still plenty of time left too.
Ideally, I would like another forward and/or a striker (if Dominic Calvert-Lewin does leave) a ball-winning central midfielder - given Idrissa Gueye's age - and perhaps a right-back too with Nathan Patterson's injury problems a real worry.
For now, Dyche and Thelwell deserve a great deal of credit for how they have successfully maneuvered in this window, despite all the difficulties, which are certainly greater than any other Premier League club is grappling with.