Was it possible that the Japs would have considered/contempl...

Was it possible that the Japs would have considered/contemplated an invasion? To what avail?

As far as I know, Japan wanted an empire in Asia and invasion was the way they tried to get it. I think those aspirations were limited to that area.

To be quick and short: no. There was no real chance the japanese could mount a succesfull invasion of the US mainland anyway (even Hawaii would've been untenable for them) because of their commitments at China and SE Asia. There were not enough troops to pull that off, and there was not enough shipping to keep an invasion supplied while keeping the japanese mainland supplied with raw materials.

The Japanese imperial headquarters never gave any thought to it, because they knew it was well beyond their capabilities. Their whole war plan was to kick the US out of the war by means of a consecutive series of victories over their navy, thus forcing them to accept the japanese gains in SE Asia and the DEI. Japan never intended or planned to "win" a war versus the US, they just wanted to force them to accept the japanese gains of posessions on Indonesia, Burma and Phillipines.Oh, and China.

Was a gross miscalculation of US mentality, BTW. Their whole strategic planning was FUBAR everywhere where the US was involved. For starters Roosevelt would've never accepted the japanese gains, no matter how victorious the japanese were in the first stages of the campaign: it was plain to see that in the long run there was no question of who would win. And then the whole diplomatic blunder they commited with the surprise attack on PH and the terrible timing error they did on the declaration of war only guaranteed both the US high-level commitment into the war, aswell as ensured the US common people to be enraged and to demand revenge.

the whole Far Eastern theater during WW2 was a consecutive series of misinterpretations and underestimations of the enemy, from both sides. The complete lack of understanding and continuated underestimation of the other side's culture and capabilities was one of the vital factors both in why the war started, how it was planned by both sides, and how it was conducted by both of them. No side followed the excellent "know your enemy" advice Sun-Tzu already had given 3000 years ago...and well, both sides paid heavily for it.