Question: Can offerings made to the Buddha(s) or Bodhisattva{s) at their shrines be made to the deceased?
Answer: Yes, they can be re-offered as suggested, after reasonable time, such as the span of a meal. Although the food is not really eaten, it is only appropriately courteous to wait a while, since making of the offering is supposed to express reverence and generosity.
Incidentally, such Buddha-Bodhisattva post-offered food is often regarded as blessed, and such food should not be wasted, as it can be offered to everyone else, including the deceased and alive.
Question: Can offerings made to the deceased at their shrines be made to the Buddha(s) or Bodhisattva{s)?
Answer: No, they should not be re-offered as suggested. This is so as the food’s essence might have been consumed already, which makes it considered inappropriate for offering to the enlightened, as this somewhat expresses the opposite of reverence and generosity.
Incidentally, such post-deceased offered food is often regarded as somewhat unhealthy by some, yet regarded as somewhat blessed by others. A suggestion is to pray over the food after removing it, by reciting the name of Buddha, but not re-offering it, asking the Buddha to bless the food, to make it safely consumable, so as to not waste it.
Related Article:
Can We Eat Food After Offering At Shrines?
https://thedailyenlightenment.com/2015/05/can-we-eat-food-after-offering-at-shrines