I know this is a long shot considering the pictures (especially the third) but I might as well try my luck. I'll add a description to hopefully further help haha.
1st and 2nd picture - this bird was seen in Victoria Point Qld. It landed on the sand bay by iteself as it was solo for a short period of time before flying off and was rather small. Sharp Tail or Curlew Sandpiper Maybe?????
3rd picture - Seen Wellington Point, QLD. These birds seemed to be constantly flying back and forth as I saw them fly past on about 5+ occasions within about a 15minute period.
4th picture - Seen at Nudgee Beach
Red-necked Stint, Whimbrels & Pacific Golden Plover.
I agree with Steven