I should start with noting that we also have a Fluent category on this discourse instance, and your question is actually more about Fluent than about Pontoon.
One thing I notice, and I notice you may not have control over it, is the lack of structure around products and their variants. If you actually have a product identifier, I’d suggest to use that to look up product names.
Another thing I notice is colors. IIRC, different cultures and as such languages categorize shades of colors differently. I.e., something that’s a shade of blue in one language might be a shade of green or red in another.
As for the use of terms, I’d suggest to only use terms if you’re also using them as part of generic phrases. Then term variants and attributes become relevant.
If you’re expecting partial translations on your production system, you want to read this post: On Message- and Termreferences.
Last but not least, if you have messages that you don’t want to expose to l10n in general, you can put them into a generic FTL file, and add the same resource to all bundles you use.