more likely that Mac replaces Hendo and Thuram on left as pretty much everything i've seen has him on that side of pitch .
I think personally
Thruam is a big unit who plays left side but more of a no 6 type for me. He would be "fabinho"
Macallister as you say could well be the henderson role as a counter pressing machine.
LCM is hard to say. Jones, bajcetic, thaigo, even henderson. It would be for me more likely to be Kone's position as a more advanced unit.
IF its 433.
If we play 3223 or whatever the hell it is when trent wanders to no 6 and puts out his deck chair, then you are wide open to suggestions what to do and neither kone nor thuam make sense except to replace fabinho.
The box midfield put spaces between the back 3 to be filled by the no 6 type players. (konate sticks at rb in transition and trent dropped to CB.
The two advanced CMS are in effect false 10s. not really 8s they are miles up the park and for me that doesn't suit MacAllister really. It could be elliott or jones plus macallister there and then fill inthe front 3 as you like
.....................Alisson
Konate........... vvd............ Robertson
............Trent........Thuram
........Macallister.....Jones.
Salah..............Gakpo.........Diaz
You've then got jota, nunez, elliott, henderson, fabinho, tsimikas on the bench.
The thing is when i write this and look at how injury prone the cbs are matip and gomez start to freak me out more than not buying two more CMs.
By all means get a Thuram id price is right but we need to then think what we are doing with this system before buying again.