I took vitex to help lengthen my luteal phase. I was under a naturopath by the time I started vitex. The cycle I took it it worked and lengthened it by about 3 days. I'm not sure if it was going to continue working or not because I ended up going to see a FS and started on progesterone pessaries to lengthen the luteal phase.

IMO vitamins a certainly worth a shot. I'm not sure about adding the B complex with the folic acid on top. Vitamin Bs certainly didn't lengthen my luteal phase, but not to say it won't help you as the causes for these things are all different.

Ovulation can be seen after the fact by a temperature rise and a sustained higher temperature through the luteal phase. I found it always best to use with the OPKs because I would get mini peaks in my temperature for days leading up to ovulation. Sounds like this is what you are doing anyhow.

Wishing you all the best and speedy BFP