I did a bit of ‘research’ of my own to get up to speed with this topic too. It appears that both Velocity and Krisflyer allow upgrades using points and these are confirmed immediately if availabilities and sufficient points are available.
However, it seems that Velocity upgrade with points are only allowed for Virgin Australia flights (i.e. VA aircraft only). So you can only get to Abu Dhabi (and they have announced this route will stop after Feb 2017 recently). Unless you are looking to travel before Feb (which I doubt would be the case), you can’t use the upgrade with points method through Velocity.
Your other option, not as good, is to transfer your points to Krisflyer, 200k Vel =148k Krisflyer.
However, you would have to pay $5627 on Singapore Airlines for Full Flexi Economy instead of $4720 on Virgin Australia (to fly with Etihad).
Point-wise, you have only enough miles to upgrade Econ-Business with Krisflyer for 2 seats (63,750 miles one way pp). I believe you need 4.
I can see the following options, which make use of your points with possible upgrades:
Buy Economy and upgrade to Premium Economy (129.2k miles for 2 person return). Then buy bub's P. Econ ticket for $231.40. Total Cost ~$5700
Buy Premium Economy Seats ($5846 for 2 adult return). It cost 44.2k miles to upgrade to Business Saver per person 1 way. You could potentially get 2 seats 1 way and 1 seat the other with your existing point balance. Mum and bub can be on business ;) and you rough it out in Coach. Then buy bub's business ticket for ~$600
Note: If you are really going down the track of redeeming upgrades with points, please confirm that there are availabilities for outright redemption with points before buying the tickets. Best to check over the phone too if you are iffy with what the website says. Worst thing you can do is pay for full flex economy or prem. econ and have no availabilities for upgrade. Please also note that the miles quoted is for the Saver fares (which can be limited). Best to book well in advance too for better availabilities.
Good luck. Do report back with your decision and how you went booking and redeeming.