Can I recycle old Apple products ( iMac 27-inch, Time Capsule, MacBook) at my local Apple Store?

Generally speaking, yes, you can take your old Apple products to the Apple Store for recycling.

I've never had any problem with that the several times I've done it.

And just for grins, you might check to see if your old gear is maybe worth a few pennies on an Apple Gift Card.

Apple Trade In - Apple

I suggest selling at least the Time Capsule on your own. A significant demand for used TCs exist whereas you are likely to get nothing or close to nothing from Apple.

Same may apply to the other products, lacking any additional detail. However, you will always get more for them than Apple will give you as trade-in credit.

In any event Apple will accept them at no charge, if that's really what you want to do.