Honestly… the hexidecimal idea is terrible, from an in character perspective. It's an incredibly inefficient solution to a simple problem.
Having discovered that adding a numeric sequence to the word will allow for X number of uses, where X is the number of options in that sequence, why not just add a regular number to the word, and keep going in sequence, at least for written communication? So, like, "the 1object was cross tested with a small alpaca, who looked at the 2object but did not interact with it. the 3object remains unharmed." or whatever. That leaves a theoretically infinite number of uses for the term, although for practicality's sake you'd have to swap to an alternate numeric system once it hit ten digits or so to avoid taking up too much space on the report. That shouldn't be an issue, though; I don't expect the report would need to use the same term thousands of times.
Yes, I'm aware (as an in character point of view) that the hexadecimal system applied to write a report about this SCP is terrible. It makes writing reports a tedious (even excruciating) ordeal. As a matter of fact my first idea would be even more tedious: all words in the report must apply a set of IPv6 address.
Somehow I found that the image of a researcher writing a heavily hex-coded report and cursing (in the mean time this SCP's effect kicks in, and makes it harder and harder for him/her to curse) very amusing.
Another idea I've came up with to describe this SCP in writing is to use "_" between every word, thus making every sentences as a "word". Example: SCP-KEY_is_a_metallic_key. Not sure if this is better than the previous hexadecimal system but as an in character point of view it would be a whole lot better and easier to describe this SCP in writing form.
Meanwhile, in spoken communication, personnel could simply ammend a singly syllable of their choice. For example, "OH MY 343! THE POOPOBJECT HAS BREACHED CONTAINMENT! I REPEAT, THE DEBOBJECT HAS BREACHED CONTAINMENT!"
I haven't thought of that in depth yet since right now I'm focusing on how to describe this SCP in writing form. I think your idea sounds promising and I will to give it a thought in depth.
Of course, this raises the question of how the object would respond to homonyms. Would "too-object" and "two-object" cancel each other out when spoken aloud, or would they be acceptable because they're different syllables when written? For that matter, would "object" and "ahbject" both be useable? if so, you could just keep coming up with variaations and phoneticisms ad infinitum.
I believe according to the rules I've set up so far, homonyms won't count as long as people who said it IS thinking another word at the time. However I'm not sure if this is really as "ad infinitum" as it sounds. I think I'll do some research about this matter this weekend.
How about alternate spellings? Could "1object" and "oneobject" both work?
Yes, I believe that would work as well. If the word "1object" is already used, you can switch to "oneobject" instead.
Yes, the effect will still apply with made-up word.
Do prerecorded terms work? If a researcher simply said "key" into a tape recorder, then pressed play each time he needed to refer to the object, what would happen? If the effect didn't somehow erase the tape, the researcher could simply use a tape recorder and speech-to-text program to compile the report and avoid the issue entirely, since you've already told us the effect doesn't apply to software.
The effect does not extend to non-human subjects, let along erasing tapes. I see where you're going, and this might be the solution for our spoken communication problem. All researchers can be equipped with a speech synthesiser (like the one Stephen Hawking is using) for verbal communication.
In short, I'm getting the sense that you're stuck because you haven't really thought this one through. I'd advise you to sit back and maybe work on something else for a while until you have a better idea of how the anomaly functions.
I think I'll do more readings, and simplify my ideas about this SCP. Thanks for your suggestions, it did helped a lot.