actuarial suicide
4 hours a day? Every day? Really?
I agree these are the hardest three CTs you can do, but if you put in the hours (without going insane), I don't see why not. The recommended number of study hours for a CT is 125-150 I think, but it may be that something closer to 200 is needed for these three. Maybe 500 hours total, say. So you could do it with an average of 3 hours a day for the next 6 months, but I think you really need to question if you can keep that up. But if you can, why not?
Your expected number of passes may increase, but the volatility of your result will increase too. Would you rather have a 70% chance of passing two exams, or a 50% chance of passing three?
Might be worth checking they're not too close together in the schedule too - a few days in between the exams would be a big help i'd imagine.