In other words, someone who is excommunicated is not necessarily socially shunned by TFI members. Is that a correct conclusion?
Yes, that is correct, though more often than not the individual would
be socially avoided, if not shunned, especially if they were thought to be "spreading doubt" (i.e. trying to encourage others to leave, talking about how their life has improved outside the Family, speaking against leaders, etc). Other factors such as the offense & circumstances under which they were excommed, whether the individual continued to support the Family, and so on, could certainly also affect the level of social interaction these individuals might experience with Family members.
I find it very hard to believe that the Family would ever turn down money from an excommunicated member, unless it would notably damage their PR image. Consider the well-known (within The Family) story The Loaf of Bread
. The entire build-up serves to deliver the line "Thank you
Jesus [for providing], even if you had to use the devil to bring it."