The colon is fine; however, our Rule 1a. of Colons says, “Use a colon to introduce an item or a series of items. Do not capitalize the first item after the colon (unless it’s a proper noun).” Therefore, do not capitalize the word all immediately following the colon.

She imagines all the things that the tree must have seen over the last 50 years: All of the children climbing on it, the tire swing that she used to love daydreaming in, her brother climbing up to the top, and all the squirrels that used to play around and on it.

This seems to be a formatting preference rather than a punctuation rule. Spacing is the writer’s choice.

Example:

The client endorses the following:
– Depression
– Anxiety
– Fear

OR

The client endorses the following:

– Depression
– Anxiety
– Fear

Your first example sentence with the commas is correct. Semicolons are used to separate units of a series when one or more of the units contain commas. See our Punctuation Rules for more information.

If your list contains only two items following the colon, you might consider writing it as:

The barn was designed with two goals in mind: 1) education offering walking farm tours to help guests better understand sustainable farming and 2) entertainment featuring private lunches, dinners, and corporate events

If you must use “first” and “second,” we would write it as follows:
The barn was designed with two goals in mind: first, education offering walking farm tours to help guests better understand sustainable farming and second, entertainment featuring private lunches, dinners, and corporate events.

The barn was designed with two goals in mind:

First, education, offering walking farm tours to help guests better understand sustainable farming. Second, entertainment, featuring private lunches, dinners and corporate events.

Since you are not using a tabular format, we recommend the following:
The symbols on the side panels signify six Corporal Acts of Christian Mercy: feed the hungry, give drink to the thirsty, clothe the naked, give shelter to travelers, visit the sick, and visit the imprisoned.

The symbols on the side panels signify six Corporal Acts of Christian Mercy: Feed the hungry. Give drink to the thirsty. Clothe the naked. Give shelter to travelers. Visit the sick. Visit the imprisoned.