I'd say it's probably about 95% certain that Alain will stay in the band for the next shows. His return seems to have gone pretty well to date, and Boz appears to be doing his own thing these days.
And no new goss on the new album that I'm aware of.
The latest was that he'll be previewing songs off it in the next batch of shows.
I would guess yes on Alain playing at the UK shows. If you're asking about a release date for Bonfire of Teenagers, nothing has been said publicly. As far as we know Morrissey is still without a record deal. Over a month ago, he said that I Am Veronica was his next single... but there's been no further word on it other than this digital mockup. So, as usual... more questions than answers.