It's VERY possible to conduct operations, switching, etc., with conventional postwar equipment. I personally had no problem with the F-N-R sequence of the e-units. Some modern-era freight cars were too light or balky for reliable coupling and uncoupling, so we made a rule that if it doesn't couple or uncouple on the first try, lift the car and engage the couplers by hand. Yes it spoils the illusion a bit, but it's the only way.
For a multi-operator conventional railroad, you'll need electrically insulated blocks and probably some type of cab control system. Folks did it this way for almost 50 years before command control. Your Z-4000 remotes will provide freedom to walk around with the train if that's what you want. If you ever decide to go command, you'll have to install an ERR AC commander in each loco. Right now that's about your only option for Postwar.
One limiting factor you'll have is room size. Compared to N, O gauge takes up a LOT of space. Depending on your room size, you might find that a double mainline works better for multi-train operation than a single one. Or perhaps a single track main, and a yard with a lengthy lead independent of the mainline that serves a couple of industries. Especially if you're using Postwar equipment, don't be shy about using sharp curves. Those traditional trains look pretty good on 21" radius (aka O42). Personally I wouldn't build a new layout with O31 and Lionel #022 switches, unless that's all you have. I've been begging Steve at Ross to make his great switches in O36. Keep bugging him and we'll all have more options!
The next factor variety of operations is the number of turnouts / switches. Quality switches are EXPENSIVE! There's no getting around this, so don't cheap out and buy someone else's used junk. If you're going to build a layout with 20+ switches in a spare room, your trains will be passing over those switches several times a minute. So you want good ones that won't cause random derailments every third lap. Again I would recommend Ross, although some folks have good experience with Atlas O (if you can find them!)
The final limiting factor that led me to give up on Postwar, is slow speed operating characteristics. I love steam! But most of the postwar steam locomotives just won't operate for any significant distance at realistic switching speeds. The gear ratios are all wrong with no obvious way to improve them. Unless your layout is dead level with excellent power distribution, you'll have to jockey the throttle just to keep the speed under 25 scale MPH (a convincing slow freight.) This is especially true once the motors are warm, or the locos are running light without a train. For me personally, "toy train" speeds spoil the illusion and make it apparent that you're just going around in circles. The 773 Hudson is ok, but it's scale-sized and pretty big for traditional trains and Plasticville buildings. You might also be able to find a prewar 227 steam switcher and install Postwar couplers. So your choices for steam are very limited.
If you like diesels, you have some good options. Dual-motored F-3's, FM TrainMasters, GG-1s will run as well as any modern era loco without speed control. Good-quality single-motored locos like the 622 switcher, 2023 Alcos, GP-9's should be operated in pairs (the two independent motors "help" each other, and even out the power pulses at slow speeds), although 25" of locomotive is a luxury on a small layout. The little motorized units run slower, but they're noisy, maintenance-intensive, and can only pull a few cars.
Bottom line, you can definitely build a multi-person operations-oriented railroad with Postwar equipment. The four considerations you have to deal with are a block system for independent control of conventional trains; a track plan that supports purposeful multi-train operation; quality track switches; and motive power that runs smoothly at scale speeds. I wish you luck and think it's very worth doing!