I'd say OIO approval is fairly certain given Tegel is 45% owned by a Singapore based private equity fund now and was 100% 2 years ago. Its just a change of overseas owner from a financial owner to an operator owner who is probably more likely to get a decent return from the assets.
$1.27 with the dividend included is a fair offer in my opinion and I'd say the deal is 80% likely to succeed as it stands now - not a great result for IPO holders but there will be plenty that bought at $1.10 or lower that will be quite happy with the result. The offer is just over 8x EV/ebitda which is similar to the IPO metrics except the ebitda has deteriorated 10-15% since the IPO 'forecasts'...say no more.