Oh, not back to yesterday? Back to any time/place for a day?
I think it would be too hard to access any of these events or people - you'd go back then just end up in jail or something. I would like to see the moon though, so if it's a literal anything is possible situation I'll hitch along with those guys, on the first moon landing.
For front splits: Very deep lunges to stretch hip flexors, hamstring stretches, then get as close as you can, preferably supporting your crotch ('sit' on a small stool, then a yoga block, whatever supports you in the position) so that you can relax into the pose.
Best to do these after a workout while you are warm, then again before bed when you are cool, and go to your edge but not past it, that edge will move.
For straddle split, I don't know if everyone can get those but my nearly 60 year old husband can, and mostly he just lifts weights, so maybe. Those you can practice hot or cold, and if you do the widest you can and lean forward for 5 minutes it will also relax you for sleep. So good practice for bedtime.