Need some advice on daily calorie intake and other stuff

I have some questions and I'm not entirely sure I can word them correctly or so that they make sense, so please bear with me as I attempt to explain my confusions. About 4 weeks ago I started Mark Lauren's YAYOG DVD set thanks to a recommendation from a helpful individual here on the forums. I'm on my third week of the intermediate level, planning to move up to advanced either after this week or the next. I love the program and I've lost a few inches and everything seems to be going well. I would also like to add in something additional for my off days because I feel like working out 3 times a week is not enough, I'm just not sure what as of yet. I'm currently trying to shed fat but maintain my muscle (skinny fat), and as I'm unable to lift heavy at the moment, I decided to start with YAYOG.
In a nutshell, I just want to be sure I'm fueling my body. I'm perfectly content eating at 1321 (see below), however I don't want to hurt myself in the long run. I'm able to fulfill my macros (MFP defaults) and I hit all my levels pretty regularly. I prefer to be able to eat at a set calorie allowance each day, rather than eating exercise calories back as I'm a creature of routine and I typically eat the same stuff. I would be content eating more on exercise days than non exercise days at a set amount for each day, however I'm not sure how to figure out what the calories would be each day. I have a heart rate monitor (polar something or other) but I don't use it because a) I rarely eat my exercise calories back and b) I've heard they can be inaccurate, especially for resistance training.

Stats:
28 years old
Female
115#
5'4"
YAYOG 3 times a week (recommended per the program), plus hiking, dog parks, walks multiple times a week, and out and about/keeping up with a very active 8 year old son. I'm a tech at a vet clinic so very busy, on the go when I'm at work (35-40 hours a week). I'd like to think I'm pretty active for the most part, although I'd imagine that's subjective.

On Mark Lauren's website I get a daily calorie allowance of 1321, but that is with a generic "less than 50# to lose". The choices are maintain, gain, <50 or >50 to lose. This is what I've been doing for the last 4 weeks or so.
MFP gives me 1470 with 0.5# loss a week, lightly active.
I've looked into TDEE but I feel like it gives me too many calories, which means I'm either over-stating my activity level or it's a mental issue. I also find it confusing and/or not logical as to why I would be eating the same amount every day (at an amount higher than what I am currently eating) even though my activity level is not exactly consistent day to day.

I guess these would be some of my questions:
-Are the MFP macro defaults ideal in this case?
-I've read that in my situation, eating at maintenance and working out is the ideal approach. If I'm eating at maintenance, how will I shed fat? Is YAYOG enough?
-Can I add in another workout routine for the days I'm not doing YAYOG? If so, any recommendations?
-Any general tips/recommendations? Sometimes I feel like I'm just floating along with no guidelines and that makes me frazzled; I really need structure to maintain my sanity.

I'm not really focused by the number on the scale, just trying to shed inches. Hopefully I'm able to make sense and thank you!