All over the internet and flyertalk and blogs - expected in June this year latest by year end.

AS
HI and AS merged - miles transfer came quicker than expected. Only HI cardholders can transfer miles for free. So we have all sent our AS miles to linked HI account and then pooled them in 1 HI account and then to 1 AS acct.
70k HI for 2k spend = 72k cost 99+80$ lost cash = 180
50k for 4k spend business = 54k = 99+160 = 260
70k AS for 3k spend = 73k = 99+120=220
70k AS for 4k spend = 74k = 99+160 = 260
Total = 273k per person for 915$ = 0.3c cost x 8 = 2.2M miles on AS for about 7400$
The programs are due to merge later this year and Barclay cards will no longer be issued after 2025.

AA
Cit and Barclays both issue - Citi plans to take over the accounts = Expected by Next June - latest by year end next year
Similar story with apps - do Barclays first - Citi will remain with their 48 month rules
Barclays uses 25 month rule for new cards bonuses on Same Card
Again do Barclays first - you can do Citi next year anytime

Between AA and HI do HI first as that merger went through first and their merger action seems a lot faster than expected.
Even if you do not get to merge all family miles, at least get going on the HI miles as they can be sent to each persons AS account at least and will not be lost
Since we wanted to pool in 1 AS account we opted for HI/HI/ AS/AS and are hitting AA & AA last
Your timeline can be different