As the head-coach,
Pochettino would have a huge influence over the incoming players and it's naive to think a head-coach/manager does not know about the attitude of the players their club is buying. And if he didn't he's still partly at fault.
Just recently the Norwegian national head-coach, Ståle Solbakken, told about a meeting he had with Pep Guardiola (in Manchester) where they, of course, talked about Haaland...and he was surprised about how much Guardiola knew about Haaland as a person.
You're insinuating that Liverpool bought Salah against Klopp's will but it was simply the case of having him change his mind by convincing him Salah is the better option.
Jurgen Klopp was convinced to take Mo Salah last summer when he really wanted a different target.
www.football365.com
And German journalist Raphael Honigstein has claimed that Salah was not Klopp’s top Liverpool target back in the summer
Instead, he wanted Leverkusen star Brandt, but Reds sporting director Michael Edwards intervened in the matter.
“Michael Edwards had been getting a lot of criticism in Liverpool for some of the decisions they’ve made over the last few years,” Honigstein told the Totally Football Show podcast.