More hints at a Butler trade?
Maybe.
OTOH, it's hard to find a year in which BB hasn't added 3-5 DBs to the off-season roster during draft weekend, nearly always spending at least one pick, and ofen two picks, in addition to signing 2-3 UDFA.
They've had a couple seasons now to evaluate Coleman, King and Richards for developmental upside, and a year with Jon Jones. King and Jones appear to be solid, high-use special teamers, but they haven't seen many defensive snaps (King had zero in 2016). Both are probably on the bubble by default.
Coleman appears to be an "okay" backup, but one who could be upgraded. He also lost significant defensive snaps almost immediately after the Pats acquired Rowe in mid-season, which could be a sign that they don't see Coleman ever becoming a starter. Coleman also didn't contribute much on special teams (only 65 total snaps in 2016). So, he could be vulnerable to Camp competition from a rookie. OTOH, he's had enough game exposure that there may be a slim chance that the Pats could get a 7th for him at some point, perhaps during Camp.
I don't know what to make of Richards. He didn't see very many defensive snaps last season, or all that many ST snaps, either. Going into year-3 of his 4-year rookie contract, I'd have to guess that he's vulnerable to being cut in Camp unless he shows a significant developmental leap this summer, either defensively or as a special-teamer.
Anyway, I don't know that the Pats have had an unusually high number (for them) of contacts and/or PWs with DBs this year compared to previous years. It could be that these interactions merely seem more significant this time around because of the Butler situation.
It's entirely possible that Butler gets traded, still. Might happen between now and the draft or on the first night of. But it might still even happen shortly AFTER the draft, if BB "gets his guy" who he thinks could quickly replace Butler.
It also could be that BB is merely keeping the developmental pipeline full in case Butler plays out his tender and walks in 2018.