Given how polarizing a figure Galileo has become in recent years (he’s loved or loathed by different factions for various reasons) , I was wondering if you cut him out of the equation would Newton have gleaned enough cosmological knowledge from Kepler and others to have come up with his various consequential principles in Principia? Or were’s Galileo’s insights so integral that Newton would not have achieved his remarkable discoveries?
How polarizing he’s become… in recent years? He was polarizing in his lifetime. In the centuries since, he’s become far less polarizing.
And Kepler’s work wasn’t something that you “glean from”. If you have Kepler’s work, you have everything, and there’s nothing else to be missed. The real question isn’t what Newton could have gotten from Kepler without Galileo; it’s whether Kepler could have gotten his results without Galileo.
And I think he probably could. He still would have had Copernicus, of course, and Copernicus wasn’t nearly as toxic as Galileo. Galileo’s big contribution, aside from being a massive dick to absolutely everyone, was to make some simple, easy-to-understand empirical observations that supported the heliocentric model. But Kepler didn’t need the simple data; he was working from Tycho’s data, the best, most detailed, most extensive, most precise astronomical data in the world at the time. It took a lot more data-analysis chops to work with all that precise data, but that was Kepler’s whole schtick.
Galileo didn’t invent anything - he discovered and defined things that already existed. If he hadn’t done it first, someone else would have. Science’s progress is not dependent on any individual.
Could you provide a link regarding the increasing recent controversy over Galileo? I was unaware (and as a non-scientist have long been interested in the history of science.)
Galileo was certainly controversial in his lifetime - although he was only sentenced to house arrest at a time when people were executed for minor crimes -but I am not aware of any controversy now.
To your question, I think Newton would have worked out a law of universal gravitation based on the laws of motion and observations of objects falling to Earth, even in the absence of Kepler. And if Newton hadn’t done so, someone else would have. Robert Hooke was working in the same lines.
In 1999, Time/Life Books released The Life Millennium: The 100 most important events and people of the past 1,000 years.
In their list, they ranked Galileo as being the #4 most influential person of the past 1k years, which I think is too high. But since these people put Edison as #1, a case can be made that the list makers were morons.
Anyway, if there isn’t a controversy, we can most assuredly make one: Galileo is extremely overrated, nothing more than a media creation of anti-Catholic, pro-Protestant interests which should not be trusted. “Oooh, look, he rolls balls down a ramp! Brilliant!” 
In our game of a decade ago, we put Galileo @ #56, a much more sane ranking:
Btw, Discourse somehow is getting the numbers wrong. If you click on the link, Galileo is #56, not #60 as shown in the preview window.
It’s also in the opposite order. It looks like Discourse thought “Hm, here’s a numbered list, and the first element in that list is 58, therefore the next ones must be 59, 60, and so on”.
That hack, Galileo, strikes again!