You’ve presented a number of different scenarios, without a lot of specifics, so I’ll start from the top, and from a US perspective.
A very generic term that would come up in this situation is material misstatement. one might say that an account or line item is overstated or understated, or a misstatement could arise from the omission of a necessary note, because notes are an integral part of the financial statements. Financial statements are said to be materially misstated if the misstatement would affect the choice of a typical decisionmaker. There’s no explicit standard for what is or isn’t material, but in practice, auditors often choose some small fraction of net income as the threshold. Materiality can also be caused by positive vs. negative earnings, or other thresholds, like financing agreements which might oblige the company to keep its current ratio above a certain level, for example. In the US, the rules to which the statements have to be materially correct are known as GAAP (Generally Accepted Accounting Principles) and they are codified in the Financial Accounting Standards Board's Accounting Standards Codification (FASB ASC).
Depending on how the scheme is arranged, issues in the realm of “buying stuff as a “customer” to make the business look good” include:
Substance over form: it may not be appropriate to recognize as a sale at all. If the net effect is a transfer of cash from the owner or manager to the business, while the goods find their way back into the company warehouse, that could be considered as paid-in-capital, or even a liability, rather than a sale. Owner bought some product to inject cash, and put the goods back in the inventory? That’s cash from the stockholder, not a customer sale. Somebody in management moved a truckload of product to his storage unit, only to return it after year end? That might be more accurately characterized as a loan, not a sale. I don’t know of any specific terms for this exclusively, but there have certainly been cases where companies moved inventory to undisclosed warehouses in an effort to hide fictitious sales from their independent auditors. Edit: Another term for certain sales without commercial substance is a “roundtrip transaction” or “roundtripping.”
Disclosure notes: even if there is commercial substance to the transaction, it may require disclosure notes, such as those for related party transactions, as required by ASC 850. Transactions with related parties must be disclosed even if they are not given accounting recognition (ASC 850-05-5). Examples of related parties are given in ASC 850-05-3, including “an entity and its principal owners, management, or members of their immediate families,” among others. Under the relevant definition, a person does not need a formal title to be considered a member of management (ASC 850-10-20). The related party disclosure is not required in consolidated financial statements, for transactions that are eliminated in the consolidation process (ASC 850-10-50-1). For sales from a public company to a bona-fide external customer, there’s also the major customers disclosure, but the threshold for that is 10% of revenue, which is much more than enough to materially impact the bottom line.
Generally, transactions between a parent company and a subsidiary will be eliminated in the preparation of the parent’s (consolidated) financial statements (ASC 810). This means if the parent company A sells goods with a carrying value of $30 to its subsidiary, B, at a price of $50, A doesn’t recognize that $20 gross profit until B sells the goods to an outside party. Internally, B might carry the goods at $50 on B’s books, but A would have to cancel it out so that only $30 of that appears on A’s consolidated balance sheet. The consolidation method is applied when one business has a controlling interest in another, and in summary it means that the parent company reports A+B’s financials as if it was all a single entity. That means B’s assets and liabilities, revenues and expenses, are all reported as part of A. It also means any transactions between B and A are transactions within the entity; you wouldn’t recognize a gain or loss (nor revenue and GP) if your marketing department sold office equipment to your engineering department, and you don’t get to with subsidiaries either. Consolidation requires not only eliminating revenues, cost of goods sold, and excess carrying value of inventories on intra-entity transactions; it's also gains and losses on things like equipment, meaning the same transaction could require a consolidation adjustment twenty years later to eliminate excess depreciation expense. Long story short, ASC 810 deals with consolidation, and those rules apply when you create or purchase a subsidiary to buy your stuff, or use a subsidiary to pass the same $200,000 back and forth.
When the parent entity does not have a controlling interest in the investee (the basic threshold is 50% of voting shares, or by some other agreement) but does have significant influence (representation on the board or other factors in ASC 323-10-15-6), then it will be treated as an equity method investment. Instead of adding the line items together, it's a single asset and A's portion of B's earnings are a single line item on the income statement, but the adjustments are similar to those in a consolidation.
Another kind of revenue recognition game which companies used to play involved bill-and-hold arrangements, wherein the customer (or the “customer,” or a salesperson without any real input from the supposed customer) would place an order, and the company would send (or at least, prepare and book) an invoice (revenue), but not ship the goods until the customer actually asked for them. These days, the rules on revenue recognition are fairly guarded against these kinds of things, but some other examples of “sales” that aren’t really sales include consignment arrangements, repurchase agreements (could be a sale with right of return, or depending on terms could be effectively a lease or a financing arrangement), and the gross vs net revenue issue for principle/agent situations (airline and hotel booking sites are a popular example. If they’re an agent they’re required to report their commission on a net basis but would likely prefer to look bigger by calling it a $110 sale and $100 cost of goods sold, instead of just $10 revenue).
If you’re interested in management schemes to mislead the users of financial statements, check out the SEC’s online archive of Accounting and Auditing Enforcement Releases (AAERs) here. Some of them just deal with individual professionals who should know better, but they can be pretty interesting, whether they involve poor ICFR, or intentional deception on the part of upper management (it's on management either way).