And peace be upon you and the mercy of Allah and His blessings.
Answer 1) It has been reported that the reward for prayer, fasting, charity, pilgrimage, and every good deed performed by a believer or a righteous child on behalf of the deceased reaches their grave, and the reward is recorded for both the one who performs it and for the deceased as well.
In the authentic narrations from Umar ibn Yazid and Hamad ibn Uthman from Abu Abdullah (peace be upon him): The deceased benefits from every good deed, to the extent that if they are in distress, they are relieved, and it is said that this is due to the actions of their son or brother.
In another narration, I asked: Can two people share in two units of prayer? He said: Yes.
And from Hisham ibn Salim from him (peace be upon him), I asked: Does prayer, supplication, and charity reach the deceased? He said: Yes. I asked: Do they know who did that? He said: Yes. Then he said: They may be displeased, but they will be pleased with it.
It has also been reported from him (peace be upon him) as previously mentioned: Whoever among the Muslims performs a good deed for a deceased person, Allah multiplies their reward and benefits the deceased through it.
Answer 2) Regarding the Takbirat al-Ihram, the ruling is as follows:
Grand Ayatollah Sayyid Sistani (may Allah protect him):
His prayer is invalid as a precaution, even if he was ignorant, due to the failure to perform the Takbir according to the accepted method, not due to the addition of the 'wa' (and).
Grand Ayatollah Sayyid Khamenei (may Allah protect him):
The prayer is invalid in the mentioned manner, even if it was an oversight.
May you be successful in all good.
