Hey there - congrats on your offers!
Context: I'm from SE Asia; got offers from Wharton $$$, Chicago Booth and LBS $; chose Wharton; transitioned to McKinsey afterwards for 4 years and now live in the SF Bay Area working in tech. (NB - I switched geographies, function and industry when I moved into mgmt consulting in the US. FWIW, I did spend 6 months in McKinsey SEA, as well, so have some insight there). So I have some empathy for the decision that you're making. : )
The biggest piece of advice I have is not to over-state the school's role in preparing you for a future job - any school can only do so much to prep you, 60-70% is really down to you. If you're interested in transitioning to management consulting, there's no meaningful difference in how either school preps you to be successful.
If I were you, some thoughts I had and questions I would ask when evaluating the different offers:
(1) How strong are the two programs in Asia / Australasia? INSEAD is strong in SE Asia but so is Wharton. (When I was a Wharton student, Wharton alums were the heads of the central banks in Malaysia, Indonesia and Thailand lol.) Honestly, I think it would be a wash for how either program sets you up in SE Asia. No clue about Australia - but I'd investigate if I were you, for example by asking to speak to alums in Australia. (NB - If you were recruiting for Europe, no doubt that INSEAD would win. If you were recruiting for US, Wharton would win.)
FWIW, in recruiting at McKinsey SEA, no one really cares whether you're from HBS, Wharton, or INSEAD. (There's a set of core schools that they recruit from - which includes both Wharton and INSEAD - and they care about whether you're in that core set or not. Now, if you were coming from Michigan, that would be a bigger issue - no disrespect intended to Michigan.) Bear in mind, though, that it's your PERSONAL attributes that mean more for recruiting - not what school you come from. Both schools will land and prep you for an interview equally well at McKinsey SEA, but you really need to pass the interview on your own.
(2) 1- vs 2-year program: I think your points about ROI and having the opportunity to explore opportunities in a less risk-free manner via a summer internship are valid. FWIW, my personal opinion in choosing a 2-year program was that ROI alone is a limited metric -- there's more to life than maximizing ROI after a certain point - and I figured the long-term ROI would sort itself out. I was also conscious about making a transition into a new industry, so wanted to manage the risk through the summer internship.
If I were you, I'd explore with INSEAD about how many students successfully transition INTO consulting from elsewhere (vs. existing consultants who are sponsored by their firms to get an MBA), and how the school prepares students who are trying to make the switch. (I imagine they do a good job, but maybe good to probe this more deeply.)
(3) Qualitative factors: Looking back at my time at Wharton, if I were thinking about what I wish I knew when I was making a decision between my offers - I realize I under-estimated the "qualitative" factors (no surprise given Wharton's focus on analysis lol). Specifically, I didn't realize how much my perspectives and horizons would be broadened by my classmates who were brilliant and ambitious and many of them interested in completely different areas such as tech and entrepreneurship. Many of my closest friends are from bschool and I continue to learn from them as we move into different paths. (I just came back from Singapore, where I officiated a bschool friend's wedding.) The challenge of course is that this is a hard thing to evaluate - esp when you live in Asia - but now that you have the offers, I'd ask the admissions offices to speak to current students and recent alums. See who you like better, who you can imagine sitting in a class with, and who you can most learn from and teach. It's a bit touchy-feely, but it's a real thing.
Good luck!