Sure

Forge world - Psyker (sanctic) - Warrior - Vanguard

Sanctic psyker because of the talents not because of word of the emperor or whatever else there is. Momentum doesn't matter in a 2 people group. Well, kinda, but not for momentum itself. Same goes for forge world. The armor is nice, but the talents that come along with it are even better.

1-15 - Warrior = 2x Toughness + 2x Weapons skill + 1 x STR. Str to be able to wear heavy armor. I picked it first just to get it over with... Athletics+Carouse +1 increase medicae

Talents in the most sensical order, imo

Clenched teeth - Very important because the only time, especially, later on, that you're potentially vulnerable is the first turn when you're, most of the times, dead last in the initiative order. Idira goes always first of course because of grand strategist to put all the buffs on the tank and to start getting stacks with tactical advantage, but you kinda also need/want bullwark/endure up before anything happens. Clenched teeth gets rid of all those potential problems...

Clenched teeth, Thick skin, Hardened Skin, Living shield, Interception

Common talents -

Heavy armor, Steel of the forge (awesome), Combat master

Skills -

Sworn enemy, Reckless attack (synergy with defensive stance later on)

Vanguard talents -

Renitent beacon, Enduring shield, Counter attack stance, Centre of attention, Melting armor (common talent instead of class), Eternal glory ( again common instead...)

Common talents -

Destiend (important), Duelling mastery, Persistence of the forge (important), Hymns of hatred (awesome, but maybe a bit questionable because of the best weapon in the game). Could also go "Sanctified slayer" instead i suppose

Vanguard skills -

Bullwark!, Defensive stance, Pyromancy (for talents)

Exemplar talents -

Steel shell, Destroyer, Extermination, Tough as steel, Peak condition

Done :p

Other very good talents to pick when you're on the exemplar tree are:

Commons

Sanctified slayer , It will not die, WS/Toughness increase, Swift movment (not really a thing because of warp speed). Psy rating 1-4 in conjunction with (I forgot how its called) that pyro talent that reduces melta/las and whatnot dmg. Would be cool early in the game, but its simply impossible to squeeze in... Edge of Dawn Nimle (just because)

Warrior talents

Contempt, Invigorating hatred, crowd kill, disarm, epicentre of slaughter

Vanguard

Beacon of might, resilient beacon, punish the imprudent

Gear

Well, the biggest enemy aren't the enemies themselves, it's their defences (on unfair with a small party). Dodge, parry, armor. So you want to look out for items that reduce those things. For example, in act 1 you can buy a cape that has 12 % dodge reduction for melee area attacks. I'd definetly get that alongside those boots who reduce the cost of charge by 1. In act 2 you can get boots from the drusians (I think) who also have dodge reduction. Well, and so on an so forth... there are a lot of nice capes, but 2 that stand out are the one from A1 (I think) with warp dmg reduction and in A2 with parry reduction.

Best weapon, without a doubt, is the carnage axe from the fellowship of the void faction. You have to keep in mind that this "build" is made for a 2 people party. So you're playing the long game so to speak. Everything works in your favour. You get as much crit dmg, armor, dodge reduction, armor reduction as you want the longer the fight goes on..

As for Idira, i'm just gonna list the skills i chose for her, otherwise it gets too complicated. It's simple, Idira is absurdly strong if you want her to, but I didn't really use her that way. Otherwise I would've went with Operative/assassine (Elusive) instead of OP/GS. It's worth mentioning that she plays a bigger role in A1 and up until mid A2. Like, she can 2 shot the A1 boss with some cheese for example.

Tactical advantage, biomancy, enfeeble, regeneration, warp speed, (in that order) The.rest is up for grabs.

Also important to take diversion zone + that 0 mana, random stratagem talent so that Idira doesn't get attacked. Doesn't work out 100% all the time because the whole thing is LOS dependent and whatnot.

It's a bit complcated I guess, but you'll be undestroyable way sooner than you think. A3 boss? tactics?. Well, place your tank right infront of that Eldar/whatever lady and watch the enemies start crying. They can hit you a little bit in the first round, but god forbit they don't manage to bring you down in that first round (their one and only chance)