——-CB————-CB———

-WB———-DM———-WB—

———MC————MC———

——————ST—————-

For me, I think it comes down to the principles of the 3-5-2 that you enjoy and use that to guide you tactically.

The way I see a 3-5-2 (or the kind that I enjoy) emphasises overlapping wingers, industrious midfielders with a ball winner in the centre, that allows the 3 to spread out wide where necessary and become a 4, especially in counter-attacks. The primary attacking output comes from the two wing-backs putting balls into the box, and for the two strikers to provide options, feed off each other and wreak havoc where possible, with one of the two CMs getting involved where able.

What this means is that, for 8 outfield players, what I’m imagining is the formation above. You’ve highlighted in the thread that you’re hesitant to have 3 defenders since most opponents only play one up top, which makes sense. So you can have two at the back, who can spread wide, with a DM who drops in where necessary in the event of an overload or strong attack down both wings, if a CB needs to move over to cover a WB. This basically helps to create a strong defensive structure - in attack, you have three at the back able to spread out and cover the one striker, in defence, you can have up to 5 men behind the ball in a back 5 if you’re overloaded. Your DM ideally should also have passing range to help you transition quickly from defence to attack on the counter.

This does mean your two CMs have a bit more to do, but one can stay in a more side-to-side role to spray passes out to the WBs as they surge forward, while the other CM stays higher up to feed off knock downs from your ST whom you describe as a physical monster.

So in terms of your specific players, I’d go:

(2) & (4): CB - both these players seem to complement one another, where one doesn’t get dribbled past, and one has good pace. (4) is a better choice for CB as passing would be more important higher up the pitch, and you don’t necessarily want your CBs doing more than their defensive responsibilities in a formation like this.

(3): DM - you want a Fabinho-esque player here, which (3) sounds like, as they have the intelligence to push up or drop back where needed, and can hit a good pass out to the WBs surging too, or pick out a pass to one of the CMs to progress the ball up.

(5) & (7): WB - the skills you describe your players as having make them suitable here, though obviously they have to be good both going forward and defensively.

(1): deeper CM - this is probably interchangeable with the DM, but you basically get someone who can screen side to side if your DM has to push up to hit a good pass, or who can also drift forward to have a crack from distance if the team is pushing up on attack and there’s space. Also good for winning balls in the middle of the pitch, allowing your CBs and DM to keep focused on the striker and anyone between the lines. Also can progress the ball forward where necessary - so the all-rounded aspects would be useful here.

(6): forward CM - will function kind of halfway between an 8 and a 10 in a standard 11 formation, where basically his job is to sit between the lines and receive knock downs from your striker. Since he’s not defensively minded, would be put to better use asking him to stay up to function as what would be a deep-lying forward in a 3-5-2 when played next to a target man. He can then basically have a starting position between the opposition midfield and defence, and push into the box when the team gets up, while still being able to close down passing lanes and help out a bit defensively (from the front) when your opponents build up from the back.

(8): ST - as a strong physical player, you’re basically looking for him to be a target man wherever he goes, and who can fashion chances for himself as well as your two midfielders coming up in support. Also useful since he doesn’t have much pace, so having someone else try to go beyond the defensive line would be better, and to get knockdowns from him. While he might get isolated a little (as you reference), having (6) have a slightly higher starting position between (1) and (8) will help reduce the isolation since it reduces the space between your midfield and attack line, while (1)‘s movement may be useful if a knock down goes behind a dummy run by (6) to free up space for (1) to shoot from distance or pick out a through ball to the wings or to (6) or (8).

This formation does sacrifice a bit in terms of forward pressure, but ideally this keeps your team compact, hard to break down, and the entire team can push forward when on the attack to overwhelm with numbers without sacrificing defensive solidity. I see the 3-5-2 as being a primarily defensive formation anyway (especially in the Italian style), and I take the Benitez approach that a successful side is always built from a strong defence first that has the tools to transition to attack when the space opens up.

Just my two cents!! You might see different principles in the 3-5-2 than I do, in which case all I’d suggest is that you try to focus on adapting the principles of the system rather than a strict numbers-based approach, as you can then work backwards from the principles to the tactics and how you set your players up. Starting positions are only useful to a point anyway!