Thanks - yeah as a US expat and citizen she still files a US tax return and the AGI is what she earns in the UK in her job here.
It is accounted for under the foreign earned income exclusion tax agreement the US and UK have so US citizens earning abroad don’t pay tax to the IRS on income already taxed provided it is less than $126 500.
We have enough savings to do an asset only application - but sounds like a joint sponsor residing state side might be a good idea.