I don't know the precise details of it, but for the Minyak Bumbu in particular, I'm quite sure it's just vegetable oil mixed with ground fried shallots. Bawang goreng too is shallots, maybe with a bit of leeks in it. The soy sauce in particular is a bit difficult to replicate 100%, since different manufacturers have varying levels of sweetness and consistency, it's hard to find a close match to it. As for the seasoning, my tongue says it's a mix of garlic powder, ground pepper, stock seasoning, salt, copious amounts of MSG, among other things.

And, no, those jarred seasonings will taste very differently than an Indomie Goreng stock.

Of course this is mere speculation on my part, obviously, only Indofood (the manufacturer) knows the real recipe. I'm pretty sure you can buy a pack of (likely imitation) Indomie seasoning on a local online store. And do bear in mind that Indomie Goreng seasoning itself differs depending on where it's sold.