Efficient insertion of deterministic acyclic finite state automaton (DAFSA) into a full-text search index?
There is (probably) no such algorithm. At least, for suffix tries it is not possible:
For every word encoded by the DAFSA there must be at least an end-of-word marker in the suffix tree. Thus, the construction takes at least $\Omega(N)$ where $N$ is the number of words encoded by the DAFSA.
This argument cannot be extended to any kind of search index because it may employ some kind of compression – like the DAFSA does.