My girlfriend and I will spend Christmas in the UK and are hoping to be with my parents to celebrate the New Year. This leaves us with the issue of needing to fly from MAN to GCM (Grand Cayman) in 1 day (Tuesday January 1st) so that she can get back to work on Jan 2nd.

This cannot be done entirely on Star Alliance, but it is possible to get to MIA in time to catch the last Cayman Airways shuttle from MIA - GCM which leaves at 8.35pm. The best option is MAN-EWR-MIA on UA (with 3.5 hr connection at EWR arriving MIA at 6.59pm). The alternative on LX (MAN-ZRH-MIA) arrives MIA at 6.05pm but adds the uncertainty of having to enter the US and go through customs at MIA. It is not possible to buy either trip on one ticket (i.e. MIA - GCM has to be bought separately but is fairly cheap so if the connection was missed it would be embarrassing (for GF's work) and inconvient but not financially disastrous!).

So my question - I guess a 96 minute connection for DOM-INT would normally be enough at MIA (having already entered the US at EWR). However as we will be on two separate tickets can the UA and Cayman Airways Itineraries be combined so that bags checked in at MAN and rechecked after customs at EWR be checked through to GCM? Or will it only be possible to check to MIA necessitating that the bags are rechecked there with Cayman Airways. Cayman do have On-line check in.

For info, I am a United Gold, my GF is a general member (previously Silver) we are non-US passport holders.

If this MIA connection is just too problematic we may have to fly MAN-LHR-MIA-GCM which can be done on one ticket but on AA or Virgin/Cayman, or else leave on the 31st and miss the New Year celebrations, so would value any opinions.