Ellis and Vlastuin, both 19 and the Tigers' first selections in the past two NAB AFL Drafts, have signed for two and three years respectively.
King's re-signing was exclusively revealed on AFL.com.au on Tuesday.
"It's good news. There's a couple of the old boys there with me and 'Kingy', and Ellis and Vlastuin … it's just a great sign of where we're at," Newman told the club's website.
"Who wouldn't want to stay at this great club?
"I spoke to a couple of those boys before and I know that they're rapt.
"For Nick, in his first year to show some faith - and the club is repaying the work that he's done already, which is a really good sign.
"The club's snapped [Ellis] up on the back of some really good form and he's one of those guys who's a gut runner and I think we really need that.
"He's a very fit boy and has provided a few goals and is a really offensive weapon for us, so we're really excited to see what he can do.
"It's a really good blend of some old and new, but I think all players are showing faith in where the club is headed."
Newman has signed up for a 13th season after he stepped down as captain at the end of last year.
"It was something I wanted at this stage of the year," he said.
"I just think it's good to know I'll be part of the group with some success around the corner."
The four players were among a raft of Tigers, including captain Trent Cotchin, Dustin Martin, Jack Riewoldt, Reece Conca, Dylan Grimes and Alex Rance, who were coming out of contract at the end of his season.
Of that group only Cotchin has recommitted so far, signing a two-year extension last month.
Jennifer Phelan is a reporter for AFL Media. Follow her on Twitter @AFL_JenPhelan.
