Migration Issues
Tongan Resources
Statistics
2011 Census [https://www.border.gov.au/ReportsandPublications/Documents/research/people-australia-2013-statistics.pdf] Other statistics about pacific islanders in general [https://www.uws.edu.au/__data/assets/pdf_file/0006/923361/SSP5680_Pacific_Communities_in_Aust_FA_LR.pdf]
specific 2011 stats on Tonga [https://www.dss.gov.au/sites/default/files/documents/02_2014/tonga.pdf]
SBS's Cultural Atlas [https://culturalatlas.sbs.com.au/] look up any culture and find out key elements of the culture and statistics about that culture in ?australia today.
Older migrants' experiences (2011)
Overview
Pacific Diaspora read as much as you can on google books to get concepts. Mostly focuses on US.
Tongans Overseas: Between Two Shores Fantastic book - available with missing pages on Goggle books. You (or your church?) may be able to purchase it somewhere.
Australian Government's perspective [http://dfat.gov.au/geo/tonga/pages/tonga-country-brief.aspx] and A Pacific Engaged [http://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Foreign_Affairs_Defence_and_Trade/Completed_inquiries/2002-04/png/report/index]
Deakin University study of all things Tongan in Australia [http://www.deakin.edu.au/__data/assets/pdf_file/0020/229502/arc-tongan-diaspora.pdf]
Federation of ethnic communities Council runs arts and community events to engage various migrant communities. This is what they did in 2018.
Student Visas
State of Education in Tonga [http://www.looptonga.com/content/tongan-pm-disappointed-declining-exam-results]
Tongan students in NZ [http://files.eric.ed.gov/fulltext/EJ768970.pdf]
Tongan Students in Australian Catholic Schools [https://www.acu.edu.au/__data/assets/pdf_file/0003/576012/Sikimeti,_Kalolaine_-_Experiences_of_Tongan_Immigrant_Students_in_Australian_Catholic_Schools_and_influences_on_their_engagement_in_learning.pdf]
Sport Migration
Australia supports Tongan sport development [http://www.ausport.gov.au/news/asc_news/story_535170_recognition_for_australian-supported_netball_program_in_tonga]
Politics of sports migration [http://www.researchgate.net/publication/236170511_Pacific_Islanders_in_Global_Rugby_The_Changing_Currents_of_Sports_Migration]
Remittances
Remittances are often based on the feelign of Transnationalism (belonging to more than one country. In this context it is important that Tonga and UAstrlia both allow dual citizenship [http://www.aph.gov.au/About_Parliament/Parliamentary_Departments/Parliamentary_Library/Publications_Archive/CIB/cib0001/01CIB05]
Pacific Islands contexts [http://www.uq.edu.au/economics/abstract/457.pdf]
Academic study of economic viability of remittances [http://press.anu.edu.au/ssgm/global_gov/pdf/ch07.pdf]
Intention to return to tonga [http://www.tandfonline.com/doi/abs/10.1080/00220389808422567] and Transnationalism in second generation Tongans [http://tlweb.latrobe.edu.au/humanities/profiles/ss/lee/second-generation.pdf]
Interesting look at influence of diaspora on Tongan politics [http://www.migrationpolicy.org/article/tonga-migration-and-homeland]
Crime (Interesting but not for your task, Ate!)
7 30 Report [http://www.abc.net.au/7.30/content/2011/s3124589.htm]