This really depends how touchflow works.
There are 2 ways. Touchflow can adress the default calander, or the actual program. In previous releases, it adressed the actual program. So big change this will be the case again. Also, from what I've seen, the only way to still open the agenda is installing a 3th party calendar.
When you launch the standarrd Calander app, it will redirect you to the touchflow 3d calender tab. I have to say it's irritating to see that there is no option to go to the real agenda.
As for pocket informant, when you install it you can work with it. Everything you fill in there will come into the regular agenda, en thus also in touchflow 3d.
I expect you won't be able to launch pocketinformant from the touchflow agenda.
(it's upto the pocketinformant developers to decide if they release a tool that integrates with touchflow 3d, but it probably will be the XDA people who will make this possible. Hopefully, with a single program instead of a full rom
I base this information on video's I've seen and past experiences with touchflow. (So haven't had the device in my hands yet)