How can i make thai search service? by analyzer and external dictionary

Elastic Stack Elasticsearch
1

using elasticsearch wants to create thai search service.
follow is the requirements.

  1. we must be consist of effective index by stemming.
  2. pre-registered terms of foreign loan words are must be included to the index.
  3. pre-registered terms of stopword dictionary must be excluded from the index.

question.
3. how can i consist 1-3 of these features at elasticsearch?
4. ICU Analyzer is meets all the above requirements?
5. how can i make external dictionary?
( include/exclude words)

Busy, but ask for help .
please.