I'm pretty sure Ostheer is dominant in the majority of those milestones.
4x mainline + 1 HMGs, they're first. (how couln't they be)
4x mainline + 1 support + 1 elite: first
4x mainline + 1 support + at snare + ai grenade: probably second behind OKW
4x mainline + 1 support + 1 elite + at snare + ai grenade: first again
4x mainline + 1 support + 1 elite + at snare + ai grenade + light vehicle (222): first again
4x mainline + 1 support + 1 elite + at snare + ai grenade + light vehicle + medic: probably 2nd depending on how you count OKW healing crate.
In fact, maybe except Brit, if you top all upgrades for USF and Soviet before teching medium tanks, Pz4 is cheaper to reach than Sherman and probably equal to T34. BUT we all know Soviet need badly the T70 to stay on the game, so if we count a T70 before going T34, the Pz4 is hitting the field before even if the Ostheer player went 251 AND 222.
Well it really depends what and against whom you are comparing and how much this makes sense. 4 mainlines or similars make sense on all factions since this is a viable build. Additional AT gun also makes sense for basically all factions, additional MG not so much since OKW and USF were not designed to use MGs as an integral part and UKF and SOV don't necessarily need one either, especially not in the early game and even more especially not in the early game against Ostheer.
Also we may should not forget to compare the strengths of the composition afterwards (and the amount of unit options each faction gets). This is obviously quite tricky and situation dependent, but at least some points can be considered. E.g. Riflemen cost more than Grenadiere. Does USF therefor draw the short end of the stick? Nope, because Riflemen are very good infantry that usually beat Grenadiere unless you go for a long range shoot out. Similarly you can argue that OST get's it's 251 or 222 faster than SOV get their T70, but that's scewed as well. Now obviously there are more factors to that like for example OST's faction design in the early game revolving around using the MG42 and Grenadiere in conjunction, but we should not leave the power level out of sight.
Also OST's tech is quite "in between" other factions, but you know this already.
Now a bit more numbers to the point with SOV T2 build, correct me if I am wrong (MP gain OST/SOV):
4x mainlines + pio:
620/570
+ 1 MG:
880/990
4x mainlines + pio + medic + AT grenade:
770(+60 mun)/945
4x main line infantry, pio, tech up to medium tank building, inclusive medic, both grenades and weapon upgrades:
1410/1460
-> For comparison at this stage USF/OKW/UKF(with bolster): 1730/1360/1870
Combined with the need for OST of building T1 first before fielding their main line, I think from the numbers we can assume that OST should have a slight disadvantage at the beginning of the game that turns into an advantage once the SOV player needs to build medics, T2 and AT grenades. Now it does not make much sense getting AT grenades at this point unless you see an OST LV, so the SOV player might postpone this until later in the game unless OST invests into a LV which would even out the costs at least MP wise. All (three) factions need approximately the same amount of MP to gain their medium tech and the standard set of utility.
Now for fuel I doubt it makes much sense to compare OST and SOV before medium tech because their teching and the units are so different. OST gets the PaK comparatively late but their vehicles early. For SOV it is completely the opposite (apart from the Clown Car). When OST gets early light vehicles, SOV can easily afford to get AT grenades and a ZiS at this point. Similarly, SOV can buy a strong T70 at which point OST surely can afford its PaK-40. So every faction should be able to field the counters at the point of game.
So, fuel gain to medium tech (medic inclusive, OKW T2 build with upgrade) OST/SOV/USF/OKW/UKF:
155/170/165/185/125
+AT grenades and weapon upgrades OST/SOV/USF/OKW/UKF(with bolster and AEC tech):
155/195/195/200/200
+ medium tank:
275/285/305/340/310
without medium tank, but +last feasible tech level (SOV does not back-tech to T1, USF only backteching for officer but not upgrade):
190/195/230/255/250
Fuel wise, the Eastern factions are comparatively cheap. Especially OST has an advantage as long as they don't need to tech up to BP3. SOV T34 and OST P4 come around the same time cost wise (bear in mind SOV always got Molotows in this case, something that is usually not needed although SOV then runs without non-doc "grenade" and T34 is generally weaker in almost all regards).
I am not sure how the newer factions can keep up with the pressure, but I assume it mostly is because of skipping of unneeded side techs that allows for earlier vehicles. We can see though that for a fully viable unlock, Eastern factions pay similar prices and newer factions pay similar prices within their group. For eastern factions, SOV gets a bit of a head start against OST until they need to build T3. Then OST takes lead being able to get their LV our early. This in turn is almost evened out once OST has to tech up to T3 and finally fully evened out at T4. OST does also not profit too much from this relatively long advantage after SOV get T3. Their pay gap between a usable light vehicle like the 222 and a built P4 is 225 fuel and they have nothing to build in between. For SOV the gap between T3 and a built T34 is 180 fuel. Fuel tech costs are very similar for these factions, especially if SOV does not get Molotows.