Britney Spears appears to be on the precipice of a mass reconciliation with her whole family -- but from the way Jamie Lynn Spears sounded Wednesday ... maybe not???

Brit's younger sibling was asked a bunch of questions about the family dynamic at LAX, and unfortunately ... she wasn't in a very chatty mood, opting to stay mum on pretty much all talk about her sister -- including the possibility of her burying the hatchet once and for all.

We'll give the cameraperson credit here ... trying to get her to open up every which way, but JLS clammed up and simply wouldn't budge. She gives a Merry Xmas though, FWIW.

Of course, regardless of Jamie Lynn's silence ... we know for a fact Britney wanted her at her birthday party this past weekend, which their mom Lynne actually ended up attending -- the first real signs of warming we've seen from Britney toward her family.

Like we told you ... not only is Brit apparently open to making amends with Jamie Lynn, but there's evidence she's keeping the window open to repairing her relationship with her father, Jamie, as well.

TMZ broke the story ... we'd recently learned Jamie had his leg amputated due to ongoing health issues, and it would appear Britney caught wind of that update too -- 'cause she posted a throwback photo of the two of them shortly thereafter.

Again, hard to gauge what Jamie Lynn's non-talking here really means -- it could suggest the sisters aren't any closer to mending fences than they were a year ago ... or, by contrast, it could also mean she's protecting Britney's privacy and they're on the road to reconciliation.

At the very least, Mama Bear is in her corner ... and that's a good start, we suppose. We'll see if the rest of the Spears brood hops aboard the love train -- for now, mum's the word.