"had to" is the past equivalent of the present tense "have to" which means necessary. Its meaning and usage is very similar to “must”, a modal verb which does not add an "s" in the 3rd person singular and is not used to express a completed action in the past.
We have to go out and vote now. = We must go out and vote
We had to ...
They are all grammatical, and vary in naturalness, but there are two different meanings.
To look at somebody or something means literally to turn your eyes so that you are seeing that person or thing.
To look to somebody or something means to expect or ask for help or some other kind of contribution. To me it seems a rather literary expression, but it may be ...
What is the meaning of your sentences?
The verb look can function as a phrasal verb so the meaning is changed depending on the preposition.
look at someone/something means to direct your eyes towards someone or something so that you can see them.
People looked at her in astonishment.
look to sb to do sth (phrasal verb)
to hope that someone will do ...
"Being" works, not "to be", because you need an absolute construction for the sentence to work and be grammatical. To have an absolute construction you need a non-finite clause with a non-finite verb, or non-predicative as you call it, but not all non-finite clauses are absolute constructions. Yes, "being" and "to be" ...
Also, you may want to look at the differences between legatee, devisee and beneficiary
Beneficiary– a person entitled to any part or all of an estate.
Legatee– a person designated by a will to receive a transfer of
personal property. Devisee– a person designated by a will to receive a
transfer of real property.