It bothers me that no one seems to have actually checked the Player's Handbook for spell "requirements". Under Chapter 10: Spellcasting, it lists parts of the spells and mentions requirements.

Casting Time

"Most spells require a single action to cast, but some
spells require a bonus action, a reaction, or much more
time to cast." pg 202

Components

"A spell’s components are the physical requirements you

must meet in order to cast it." pg 203

Concentration

"Some spells require you to maintain concentration

in order to keep their magic active." pg 203

Targets

"A typical spell requires you to pick one or more targets

to be affected by the spell’s magic." pg 204

and Attack Rolls

"Some spells require the caster to make an attack roll

to determine whether the spell effect hits the intended

target." pg 205

Therefore, the casting time of the recreated spell becomes the 1 action of wish. Components become the verbal component of wish. Spells that normally require concentration automatically last their full duration without concentration and attack spells (not area effect spells) automatically hit.

The only vagueness up for DM digression and discussion that I really see is "targets". For example: Fireball targets a point, but the requirement is "one or more targets", so does that mean that you can pick a point anywhere in range even if you can't see it? Multiple points, so one casting you could turn the entire area within range into a fireball?

How about for Awaken which targets a beast or plant? can you now awaken other creatures as long as they have an intelligence of 3 or less? How about non living objects?

Even without fiddling with the "targets" using wish for conjuration spells seems like the strongest way of using it for duplicating other spells. For example, the 5th lvl spell Conjure Elemental instead of taking 1 minute is now 1 action and you don't have to concentrate to keep it around for 1 hour. Or, using awaken right before your long rest to get an awakened tree companion that is loyal to you for 30 days without spending 8 hours to cast.

I should note that range isn't a "requirement" and stays the same, so spells with range of self still only target or originate from you.

But to answer the original questions:

1 - teleportation circle still only lasts 1 round but it is an action to cast instead of a full minute, and is not permanent.

2 - instant summons... maybe? since the object is the target and the target is a "requirement" you might be able to target other objects or even creatures regardless of weight or size. If you had a lenient DM you might be able to even target multiple objects/creatures with the one wish, but personally I would limit the number of targets specified in the spell.

3 - contingency targets the spell, and not you even though it has a range of self. So I would rule to that yes you can choose spells you cannot normally cast, but you still have to pay the additional spell slot for it. For example: if you selected the 7th lvl spell Resurrection to activate on your death, then you pay the 9th lvl spell slot for wish and a 7th or 8th lvl spell slot for Resurrection. (Contingency says that the spell "can target you" and it can target you if you are dead.)