From your list it may be that you are already or close to falling into a common mistake.
Practicing Qi Gong is a good thing at any time. However, it is NOT essential to be part of the Taijiquan workout/training…Qi gong by Qi Gong rules - Kung Fu by Kung Fu rules.
Significant portions of a true practice session will run counter to Qi Gong practice…
Warm ups - always needed…
You may consider adding in leg pressing with the bar (stretching), Stance drills…like:
Brush Knee and Twist Step across the training area over and over focusing on connecting the movement and getting the stance work good.
White Crane - focus on smooth and sinking into the empty stance…low and relaxed if possible
Lower Snake body across the area..on BOTH sides focusing on opening the hip joint and sinking
Kick with heel - both sides over and over maybe 20 each leg to start…
Lotus kick -BOTH sides…(this is the inside to outside crescent kick at the end of Yang style…)
Outside Inside crescent kick…the same number - many Taiji folks do the one in the form forgetting that if you have an outside, you also have an inside…you need to do both.
If you do a style with Fa Jing emphasis - Fa Jing drills with different striking methods…
Etc…all of this is called JibenGong - Basics. This practice is how your abilities become ingrained.
Then finish with the form…it will be harder to do after this…and require more focus.
Then you can vary it and do the form first…but ALWAYS JibenGong.
Then, if you add push hands (Tuishou)…ADD it do NOT substitute it in. Many do 90 minutes of practice…but if they do form..it is 90 minutes until they start Tuishou…then they do 30 minutes of form and 60 of Tuishou…this is WRONG. keep the old (90 of form) and ADD in the Tuishou time…this is the ONLY way to improve…continually press the level. The more you learn, the more time management and figuring out how to maintain a level becomes an issue.
Practice should make you sweat…
Then, you can cool down with Qi Gong…or choose to do Qi Gong in a separate practice time.
You need both - JibenGong and Qi Gong…