Does Buddhism have anything to say about forming such habits? Is there any knowledge -- whether in the scriptures or from personal experience -- suggesting the ideal frequency of meditation (to form a habit)?

I realize you are asking about forming habits, but sometimes the road to effortless habits are through eliminating hindrances. If we're talking satipatthana, a big deal is actually investigating hindrances to overcome these obstacles, as it is also conducive towards further cultivation of your meditation regime.

Generally speaking (vitarka), the five hindrances are:

1. Sensual Desire
2. Ill-will
3. Sloth and Torpor
4. Restlessness and Remorse
5. Doubt

Insights regarding hindrances are most likely not only beneficial for your meditation practice, but can likely be generalized to life as a whole.

More reading, and not least suggested antidotes to the hindrances:

https://www.accesstoinsight.org/lib/authors/nyanaponika/wheel026.html

Also, does consistency relative to the hour of the day of meditation matter at all?

You may benefit from looking at prolonging the time for meditation rather than increase the frequency or timing during the day. It will expose you to important observations for deepening dhyana.

Generally speaking, i'd argue that the more overall time spent in dhyana the better.

Does Buddhism have anything to say about forming such habits? Is there any knowledge -- whether in the scriptures or from personal experience -- suggesting the ideal frequency of meditation (to form a habit)?

I realize you are asking about forming habits, but sometimes the road to effortless habits goes through eliminating hindrances. If we're talking satipatthana, a big deal is actually investigating hindrances to overcome these obstacles, as it is also conducive towards further cultivation of your meditation regime.

Generally speaking (vitarka), the five hindrances are:

1. Sensual Desire
2. Ill-will
3. Sloth and Torpor
4. Restlessness and Remorse
5. Doubt

Insights regarding hindrances are most likely not only beneficial for your meditation practice, but can likely be generalized to life as a whole.

More reading, and not least suggested antidotes to the hindrances:

https://www.accesstoinsight.org/lib/authors/nyanaponika/wheel026.html

Also, does consistency relative to the hour of the day of meditation matter at all?

You may benefit from looking at prolonging the time for meditation rather than increase the frequency or timing during the day. It will expose you to important observations for deepening dhyana.

I'd argue that the more overall time spent in dhyana the better.