“phenomena”, “mental phenomena”, “thoughts” “ideas”. Literally, but not philosophically (because it’s different to how Kant used it), the best term would be “noumena”.
A dhamma, see above for translations.
No. The suttas do not use the word “object” at all. The whole point of the word “object” is that it signifies things that exist “objectively” relative to the observer. But a “sight” for example, does not: a specific sight is only seen by that observer in that moment, never before or after. Even if another person sees the same “thing” i.e. the same “object”, the “sight” they have is different.
In Buddhism, sense experience is always relational. Visual perception arises with the eye, a stimulus for the eye, and eye consciousness. These things exist in relation with each oher. Eg. if you move the position of the eye, the “sight” will also change.
For these reasons, it is always best to avoid the word “object” in early Buddhism (unless talking about material objects, etc.)
The function of knowing stimulated through the six senses.
It’s an interesting definition, rather than rephrasing it I’ll simply adjust:
Sati: That observing faculty of mind that comes face to face with sense experience with a remembering of what the experience is and what is happening in the present.