Venerable @Thaniyo_Bhikkhu ,
Regarding your use of AN3.63, although some people seem to think this sutta is clear proof that jhana can be experienced in walking meditation, it should be pointed out, however, that this is hardly a universally accepted view. Firstly and most importantly, it would make this the only sutta in the canon that mentions a walking jhana, and as sutta scholars always point out, it is much safer to look at the overwhelming general trend in all the suttas than rely on a single sutta that stands out to prove a doctrinal point.
Certainly, the commentaries disagreed about whether this sutta describes a walking jhana, and attempted to make sense of it, as Bhikkhu Bodhi, whose translation is used above, points out in his notes on this sutta:
Mp says that his walking back and forth is celestial when, having entered the four jhānas, he walks back and forth; and his walking back and forth is celestial when, after emerging from the four jhānas, he walks back and forth. This seems to imply that walking can occur even with the mind in jhāna. This, however, is contradicted by the dominant understanding that jhāna is a state of uninterrupted absorption in an object, in which case intentional movements like walking would not be possible. Mp-ṭ explains the first case of Mp (walking after entering the jhānas) to mean that he walks back and forth immediately after emerging from the jhāna, while the second case (walking after emerging) to mean that he walks back and forth after having emerged some time earlier .
There is a variety of activities mentioned in the Sutta and the sequence of events is not explictly made clear, but we can use our common sense to see that it refers to different activities not simultaneous activities. As you said in response to @Media point about this being clearly part of a retreat, it’s an indication of “a lifestyle” not activities done in meditation… When we look at this sutta as a whole, it is given to a community of lay people who were brahmins (i.e. not practicing bhikkhus). Using the metaphor of a comfortable bed, the Buddha describes jhana meditation states through allegorical imagery:
There are, brahmin, these three high and luxurious beds that I get these days when I want, without trouble or difficulty…
The Buddha is not literally resting in a luxurious bed during meditation. It is a metaphor. Similarly when describing the four postures, he uses an image than the Brahmins would understand and find appealing:
When I’m practicing like this, if I walk meditation, at that time I walk like Brahmā…
He is not literally saying that he is Brahma, (or ‘celestial’ as BBodhi has it) instead it is an image used for the purpose of illustrating a point in a conversation that has already had several allegories. Given this, it would seem unwise to interpret the description of four postures as literally describing jhana states. We should not neglect the allegorical context here when selectively quoting from this sutta in a very literal way.
Further, many people unfortunately get caught up on the various english translations of this passage (rendered as ‘celestial’; ‘like gods’; ‘like brahma’, to mention a few) but getting stuck on a translated word is a dangerously erroneous way to go about interpretation, as translation is far from an exact science. We need to rely on other contexts for more certainty. There is also much uncertainty of the original textual terms and how the meaning should be constructed. You can see the types of complexity in some of the more exasperated posts in forums like this one:
This Sutta has also been discussed here previously.
this thread
I think I recall some wit there pointed out the difficulty of walking in 4th jhana when breathing has ceased. It seems a fair point! 
AN8.30 is really about contentment. Jhana is samadhi, immersion, stillness etc . Resilience is the capacity to quickly recover from difficulties, so I’m not sure how you came to the create this sloganistic:
But for this to be true, resilience would also have to equal jhana… so I think to define it like that is an unusual oversimplification that might mislead readers here.
(Edited for clarity)