Visa advice

[Terpe]

As regards the £18k earnings, I'm sure I read before that this only applies to Immigrants wishing to brings non-EU spouses into the country. I didn't think it applied to UK citizens themselves.

I currently fall short of that earnings. With the fact she could possibly walk straight into a job, what if I obtained a letter from them saying that they would give her a job on her return, and therefore showing our combined income would take us well over that?

No.
The £18600 income applies to all sponsors of non-EU spouses.
Please do read the links I sent to you as it explains in detail what can be included.
Maybe you only need to take up a part-time job for a while.
Sorry to say there is no getting away from this income requirement just now.
Maybe this will change in the future depending on what new caselaw will be be developed. But right now it stands.

These new rules do not now allow third party sponsors nor do they take account of potential future earnings of the spouse.