Lgb mogul , great locos, moderate hauling, pull only forwar,need two hands to transport,set on rails, parts, fairly available ( cosmetic parts can be outrageous). Best on r2. Imho,these are hard to beat, if ubiquitous. I have 7....i have to say the later digital sound version with glowing firebox is hard to surpass. It would seem an old red and green 2018 might fit christmas. Black will be more $$$$ likely.
Forney, a 2-4-4t, or, 0-4-4tcan run both forward and reverse, (provided you replace the front dummy coupler. I used the very old small u shpaed lgb loop for this).
one handed transport, german and chinese are close, but german are better, heavier, better plastic. Nice for r1. Haul a bit better forward than in reverse due to weight distribution over traction tire. I love these locos, yet, the dont have the feel ofa tender loco, but are wonderful in their own way. Odd, 2ft gauge loco on 3 ft track, . Outside counterweights cranks are impossible to find should you break one. Again,i lie thesound versions. I have 3 chineseand 2 german sound.
Lgb stubbys...an acquired taste. Neither fish nor fowl. Standard gauge look, small and very ill proportioned. Heavy, smoke well, some 0-4-0 version, can pull in reverse. Not the best for heavy trains due to heft and resulting idler gear wear ( and no replacements). Sound versions are ok, but not synced with exhaust/drivers. I have the 2-4-0 and 0-4-0 version. The latter has a usable coupler on the loco front. Parts for these are nearly impossible, period. Once they wear out, id say they are finished.
Worthy of mention, the 2017 with powered tender. Not very prototypical but the older ones with 2 motors, perfect for r1 and heavy duty. Imho, they have their own lgb charm. Bullet proof. Lots of spare parts.
consider too the WPY alco diesels and uintah mallets. Both do great on R1.
I love lgb german made porters. Great Locos, again over sized in scale 1:20.5 a bit. Not heavy haulers, but respectable.
2063 davenport is a great loco, 1:20.5, performs great, but a bit mundane. A "huge" small Diesel with side rods. Kinda boring, kinda cool.
Forget olomano and chloe for any but light short running
Id suggest getting whichever one you choose, get complete and with little wear. Parts will eat any savings quickly..some parts you cannot find easily,or at all, smokers are about 25-35 dollars.