Reading the Mahavidyas as a set rather than a list
The ten are usually encountered one at a time. Taken together they describe one terrain from ten directions.
Most people meet the Mahavidyas one at a time, usually starting with Kali, and often never encounter the grouping as a grouping. But the set is the interesting object. The lists do not fully agree, the ordering varies, and the goddesses in it had independent histories before they were gathered.
That the grouping was assembled rather than handed down whole is not a problem for it. It is a fact about how a tradition organises what it has, and it tells you something about what the compilers thought the ten had in common.
The research section treats the set as its subject, with the historical material kept apart from the traditional reading and from the Trust's own.