You're in the right place, despite the name this is a board for all gameplay discussion.

I imagine it's daunting, but despite the large amount of item/map increases, the basic gameplay hasn't really changed and many of the default weapons are still considered superior. Tomislav was a straight upgrade before the health nerf, now it's up to you whether you want to use it or the default. I would ditch the dalokohs for a sandvich for throwing to your medic. Soldier loadout looks okay, but I might switch the reserve for a regular shotgun because you're lacking that 4th rocket with your blackbox, and you want the extra damage dealing potential.

Heavy: Ditch Dalakohs, not even particularly funny as a novelty item. Tomislav/Sandvich/GRU is a fine set-up, although you may get babies whining at you for using it. Swap to Minigun if there are a lot of Sentries or you're on kart pushing duty. The Sandvich/GRU combination is simply too good to give up in 90% of circumstances.

Soldier: Really you shouldn't be relying upon the BB, but if you're pubbing and can't be arsed being or babysitting a Medic it's not bad. Two things about the RS: it mini-crits ANYTHING in the air, not just conc jumpers, and its effect wears off 3 seconds after it is drawn, which not everyone seems to realise. It's good if you can consistently pop people into the air/you're fighting a lot of Scouts, otherwise the shotgun's longevity beats it.

Other options: The Liberty Launcher is good if you're REALLY struggling against Scouts, they really can't do much against it at all. Again though, that 1 less rocket makes you weaker, particularly in the air. Disciplinary Action is good if you're playing with a lot of Medics and Heavies who need whipping along a long CP map.

Demoknight: Lot of options for him, as long as you realise he's a strictly shits and giggles class and you're likely to die a lot against decent opponents using him. What I tend to use is Nades/Screen/Vanilla weapon of choice (SPANG): this leaves you with the all-conquering utility of nades, the ability to charge at point blank and do tons of damage, and gives the +25 health survivability which the Eyelander takes away from you. You might fancy taking the Eyelander instead if you're feeling brave- and the extra melee range is really helpful- but with the reduced shield protection you are very vulnerable. Remember with the Screen, for a split second after you shield bash someone your weapon is still charged- if you combo the two you should kill most things.

A more troll-y load-out is LnL/Targe/Persuader, which allows you to one-shit shit really easily and gives a hilarious amount of survivability. The Persuader was designed not to be usable with any explosive weapons, but as long as you stay close to spawn you can still refill your rage launcher. The all out Demoknight loadout is Wee Booties/Screen/Persuader, however I wouldn't recommend it.

If you're planning to do something other than pub on low skill level servers, learn to play with mostly stock weapons. Quite few of the weapons you're using reward bad positioning or are bugged/overpowered, meaning they might be banned in some servers/leagues or get nerfs in the future.