You cannot add rows via formula so some form of VBA is required

There is no significant difference in selecting via the userform vs selectiing on your sheet with the advantage there is no need to concern the user with adding rows.

able to add rows in each phase easily
vs
the people I work with wouldn't even be able to figure that out
and somewhat insulting to your colleagues.

And ypu cannot have a scrollable sub-set so you are left with having a fixed range for each phase which will have to bethe likely maximum.