In questio 4 of the I-II, Thomas discusses what is necessary for happiness. Again the distinction between perfect happiness (the vision of God) and imperfect happiness is central. Clearly this is a risky strategy, since anything that is necassary merely for the imperfect happiness that is attainable in this life could be considered ”bad”. This, I think would be a mistake though. E.g. friends are not necessary for perfect happiness, but are for the happiness that can be attained in this life.
The most important discussion here is about ”bodily perfection”, and whether it is necessary for happiness. It might come as a surpriese to some that Thomas indeed thinks that bodily perfection is necessary. He forecfully rejects the neo-platonist notion that the soul can be happy only if it is separated from the body. Thomas is a bit unclear on what bodily perfection consists of, though. It is a ”well-disposed” body, which suggests that he is primarily thinking in moral categories, not e.g. estethical, though he does say that bodily good adds ”a certain charm and perfection to happiness” (Q4, 6). A well-disposed body is a body that supports the persons striving for virtue. I guess an example would be addiction, it would be a bodily factor that hinders the pursuit of virtue.
Thomas also works with the Paulian distinction between a ”natural” and ”spiritual” body. Using this distinction he can (following Augustine) affirm that the body, when it is spiritual, is required also for the perfect happiness, since it belongs to human nature to be a body-soul-unity, unlike the angels that lack bodies. Thus humans will be equal to the angels only when they are re-joined to their bodies on the day of Judgement.