Help with Citizenship Application timelines

[Time for Tea]

Dear all

Pathway to Citizen

We are a little confused about timelines and from reading here now wonder if we can apply earlier than we originally believed for citizenship.  We are not financially in a position to use a migration agent for this and know that some of you are knowledgeable on these matters. Can anyone confirm if we can apply for citizenship after 3/6/18 this year with  one year on PR,  We think we can use the first year rule of being  out of the country for under one year  of the four year requirement count  (as we held a valid visa) and add it to our three year residency  to make four years  based on the following information ;

Our time line

Key dates

 489 Visa, pathway to permanency awarded 16/12/2012  in UK, valid to 16/12/2016.

Validation of Visa.  Date of entry/ Arrive : 18/3/2013  with three week visit,  Depart  8/4/2013.

Lawful residency date as    Moved to Adelaide permanently on   17th March 2015, with three children, we have remained in S.A  till date, except for one month in UK in May 15. 

 Applied for P.R  17/12/16 ,     Bridging Visa 17/12/2016 to 2/6/2017 while immigration processed 489 and awarded PR on 2/6/17 as conditions of visa 489 meet.

General residence requirement from Immigration website:
Australian Citizenship Act 2007 Residence Requirements

to satisfy the residence requirements you must:
⦁    have been living in Australia on a valid Australian visa for four years immediately before applying which must include the last 12 months as a permanent resident,
⦁    and    not have been absent from Australia for more than one year in total, in the 4 year period, including no more than 90 days in the year immediately before applying.
Lawful residence means living in Australia on a valid Australian temporary or permanent visa.

 

If we apply in June 18, two of my children will be 12  and 15 years in June 18 and my third will be 17 years, I understand the younger two will be on my application, unclear about 17 year old needs to apply independently   ( we would like it be be on mine if poss). The 17 year old is currently in UK ( for past three weeks), I understand that under 16 need not meet residency requirements if on parent application, not sure for 17 year old. 

Are we right to  think we will need police clearance from UK for the year we lived there that will be included in our time line for Aus Citizenship Application.

 

Thank you and await your advice.