Having gone through one major acquisition, my experience was that legal put a huge block on any technical integrations and even meetings that might reveal ip until the ink was dried. I'm skeptical they started any kind of collaborative work other than pie-in-the-sky, "wouldn't it be cool if" type meetings with lawyers present.
Correct, till all legal things a cleared upon both companies must act as there were no acquisition. Only specific M&A teams can look deeper and plan for integration.
This leads to a complicated limbo for acquired companies as customers consider the acquisition (buy now before new owner raises the price or hold out as they will cancel the product line?), employees are uncertain (conflicting products on both sides, which will continue, with which direction? Will yesterday's priorities still count tomorrow?) while all are counting their shares and make plans.
