They're all possible correct, except for 2c. I'm not quite sure what you mean by 'missing.' I think it might be different from sentence to sentence. I'll tell you what my best guess for the meaning of each sentence is based on how it's written. 1a. The business of the missing tickets. = the Event of the tickets being lost. 1b. The business of missing the tickets. = the event of people not seeing tickets they were supposed to see - OR the event of people being sad becase the tickets are lost/gone. 2a. The business of Tom’s missing the tickets. = the event of Tom being sad that the tickets are lost. 2b. The business of the tickets which/ that Tom missed. Kind of the same as 2a, but focusing more on the tickets than Tom.

1b, 2a, and 2b use "missing" and "missed" in a confused way. Better words are "losing" and "lost". 2c) makes no sense The key to understanding the first four is to focus on the object of the preposition "of": 1a "tickets", 1b "missing", 2a "missing", 2b "tickets".

2c is the only one that's absolutely wrong - all the others can be valid grammar, depending on context, but could still be improved for clarity. I'll rewrite them for you later. 1a is the business of a noun (some object(s)) - the missing tickets (aka, the lost tickets). This is not an event. About this noun you could ask "where are they". 1b is the business of a verb (an action) - missing the tickets. About this verb you could ask "when did it happen". 2a is the business of Tom's action or emotion (missing has a double meaning) (which, by the way, is about a noun). 2b is the business of the noun (which, by the way, Tom had an action or emotion about). The focus is on the verb in 2a, while the focus is on the noun (not an event) in 2b. 2c is terribly written so I can only hazard a guess what you mean here - if my guess is correct, it means pretty much the same as 2a. Now, here's how I would rewrite the five original sentences, for better grammar & clarity, while preserving the meaning (if I understood the intended meanings correctly): 1a. The issue of the missing tickets. ("The business" has a broad meaning, so "The issue" is a better word choice for precision & clarity, if I even accurately guessed what you mean.) 1b. The issue of missing the tickets. 2a. The issue of Tom missing the tickets. (The apostrophe is also fine (Tom's) but is not strictly necessary.) 2b. The matter of the tickets that Tom missed. ("The issue of the tickets" can mean something else here (ie, issuance of the tickets), so "The matter" is a better word choice in this sentence.) 2c. The fact that Tom had missed the tickets. (This is a totally different sentence structure - you could have said "The business of the fact that Tom had missed the tickets" but that would be like saying "the issue of the issue of..." which is pointlessly complicated, assuming I correctly guessed what you meant by that sentence.)