Citrus tree advice

They shouldn't need repotting yet. Check the compost and if it's very dry then give them a soak in a bowl of water and put them somewhere they can drain properly - preferably somewhere outside.

They want to be outside, but out of strong wind (which will defoliate them). They have probably lived their lives under glass so far, so acclimatise them to direct sunlight - a couple of hours a day initially, then move to light shade - to avoid burning the leaves. Don't pot on till you have a lot of roots, and then only move up one size. Enjoy them!

I would repot now, you will have to at some time so get it over with at present, try a 12" or 15" pot, although I tend to go to a 20" pot.

Compost/soil is a bit of a problem. You want something "heavier" then MPC, but my experience of stuff like John Innes No3 has never been good. I tend to mix up something like 50/50 MPC and JI N2 or 3 these days but still not overly happy.

Lemon is more tolerant of cold then Orange, so the orange will need the greater care.

Give them a good watering, if you make a mix up with MPC it will have initially some feed in it. Not sure what a good citrus feed is composed of - do have a bottle for my lime, may go read it.

Used to be information on The Citrus Centre about growing them, but have the idea they removed it or made it more difficult to read. Go have a check and see what the situation is.

I let mine just about dry out then water/feed them again, I feed every second or third time on average. The accurate description would be when I remember to and feel like it. So it is best described as Up and Down with regards watering. If outside they are susceptable to vine weeval, so expect to get a treatment for this aspect.

Lemons I have found will go outside, the leves go pale and then they grow big leaves for some reason. No idea why but you might find that one day you have new leaves 2 or 3 times bigger then the others.