Migrate articles from Drupal 6 site to Drupal 7

Hello! I need to migrate about 24.000 Articles from Drupal 6.22 to the actual 7.x Drupal, based on Panopoly distribution and Media module. The Migrate, Migrate Extras (included in Panopoly core) and Migrate D2D modules are installed already on the site. All Users, Taxonomy vocabs and terms were successfully migrated already, but the Article content type needs some special handling. Here are the "specialities": Gallery of images Old D6 site: there is a multivalue image field, created in code, which displays images in kinda "gallery" way New D7 site: Media Gallery module is used. Article content type contains Entityreference field with Inline Entity Form to reference the Media Galleries attached to the node. So migration script should create new Media Gallery with corresponding images for each non-empty image field and populate the entityreference field with node ID of the created Gallery. File path settings of File Entity Path module should be preserved by the migration script - also for migration of Body field described below. Body field Body field of old D6 site contains images inserted through IMCE, whereas in the new site the Media module is used. The Body field contains also inline inserted Youtube videos. The new site uses Fieldable Panel Panes shipped with Panopoly to display videos. For each inline video, the corresponding Fieldable Panes should be created in D7 site and atached to the node. Tags field In old d6 site this is a text field, where tags are separated by commas. In new D7 this is taxonomy vocabulary with taxonomy reference field. Besides above mentioned fields, there are few another image and text fields, which should be migrated in usual way. Please see also atached screenshot for better idea what needs to be done. Thankyou.