modkid,
We don’t know what is causing these problems, but they mostly seem to not be related to other plugins. Yours seems to be an interaction between WP SEO and NGG. I suggest that you start a new thread about “Admin blank screen with Yoast WP SEO and Next Gen Gallery” so your issue can be examined as a special case.
I’m using both those plugins on several sites and have not noticed that behavior, but I’m mostly using the Weaver II theme. One site with Duotive theme is having WP SEO admin+edit problems.
But the pair of WP SEO and NGG seem to be having trouble in your case. After starting a new thread for this plugin, you should start another thread in the NGG discussion and link to your new one. NGG recently changed to using some standard WP Javascript, and maybe something is interacting with NGG Javascript code.
There is another thread where WP SEO requires a JS .option incantation which not available in WP < 3.3, so WP SEO does have some JS issues which are unresolved. We don’t know yet the cause of what is in this thread, but your NGG interaction seems likely to be involved with the NGG recent JS changes. Although it might be that good NGG JS is being affected by WP SEO JS problems.