The question "https://scifi.stackexchange.com/questions/112626/why-do-han-et-al-go-to-maz-s-castle-on-takodana" has a good answer about ditching the Millennium Falcon because they know the First Order is looking for it in association with BB-8, Rey, and Finn.

But given that BB-8’s orange and white color scheme is described as unusual for a BB-unit by Poe Dameron, why don’t they paint him or something?

He’s a BB unit. One of a kind. Orange and white. Utterly unique and utterly invaluable.