Hi,
My first comment here, so forgive me if this is too absurd.
First of all, on the matter of posting all 4 blog posts at once. Since you insist only upon the SEO part, I would suggest posting one per week as that would prompt Google to index your site at least once a week whereas posting once a month might make Google think- this guy posts just once a week, why bother indexing every week or every day . And the freshness of the blog at any point of time is more than when you post every month.
For the second matter, posting good content more frequently is always better for SEO and for conversion. If you don't have time to write content, you can always get original content by crowd-sourcing the process. Recently I came across this website called Iwriterdotcom which offers content for low as $1.25 with ability to choose different levels of skilled writers.
You can also try other crowd-sourcing platforms and also having guest bloggers is a common practice. There are so many ways to get good content. You can post an interview with an expert of your field. Or ask a set of 10-15 standard questions to a list of say 5-10 of your friends who are involved in your field.That gives you a lot of perspectives and opinions, which you can summarize and use for your blog post.
The list goes on. Getting quality content is limited only by creativity. Be creative and think of ways to get good content without much effort on your part.You need not always think of making up the whole content thing from scratch. Just steal ideas with some courtesy just like asking questions to the right people in the right way.
Hope this is of some use.
