I doubt you'll have issues with Loot or Hack & Slash as the enhancements done really should not have impacted those products - though some of the material in Loot related to enchanting and runes may be costed differently in the future.
For the others - off the top of my head (may not be 100% accurate/complete)
Codex - again some costing changes should be expected and maybe tweaks to the spell parameters
Hack & Slash - for the combat tables should be OK as is
Grimoire - product was pulled and will not be made available - parts that could be used were included in Codex
Bazaar Annual - unlikely to be revised -
* Races - won't comply with new costing standards so they may present balance issues
* Cultures - should be OK
* Blood Talents - similar to Races
* Professions - won't comply with current costing standards so they may present balance issues
* Clerical Orders - should be OK in general, but will need tweaking to fit the spell counts
* Casting traditions - should be OK, but I have not reviewed it in detail
* Combat - effectively the same as Hack & Slash
* New Magic Items - would need detailed review, but should be OK as is
* Additional Optional Rules - generally not recommended, but I prefer to follow rules as written and don't like to apply optional rules
* Irregular Stats - don't recommend - I am a strong believer in the HARP stats being a reference to the standard for the race and that comparison between races should be applied with racial stat bonus modifiers.
* Monsters - these would require significant adjusting to comply with the new monster creation system - the old system was identified to have numerous issues and it underwent a complete overhaul - which has resulted in the basis currently being used for Bestiary, Something Wicked and other adventure and setting updates
By the way - the new elementals material being compiled by Nicholas will go much further than the short version included in HB Annual.
I hope that answers your questions. If you have any specific questions about tweaks that should be considered, please let us know and we'll be glad to provide some thoughts