Me and my girlfriend are thinking of flying to the Isle of Man, and maybe Europe at a later date, and I want to know if I can go though the non-EEA queue with her or if we have to go in separate queues upon arrival. Her passport is one that would require her to get a Schengen visa as she’s still on a student visa here and doesn’t have residency or citizenship yet.
I am in a similar situation and have visited Isle of Man with my wife. Someone with a UK visa of any kind can enter Isle of Man as a tourist (and vice versa). The likihood is you won't even be stopped because there are no routine checks.
As
@WestCoast points out, unless you are a citizen of a country still in the EU / EEA then you cannot use their queue. Some EU countries allow Brits to use e gates and then get a stamp. When EES is rolled out British Citizens won't need passport stamps and fingerprint enrollment will only occur on first entry and then first entry with a new passport. Its due in October but is looking like it might be delayed yet again. Many countries will likely allow us to use e gates after it has launched. I think you should always queue with your partner in case their is a problem. You will just end up waiting for them if you go in a different queue.
You might not know that Montenegro, Serbia and North Macedonia don't require visas for British residents. Turkey downgrades non British UK residents to a much easier e visa. Albania has e visas for a lot of nationalities that require Schengen visas. If you just want a holiday by a beach you could avoid visas if you don't mind which country you go to.