Apologies for not answering this sooner, Levistej. And thank you for the kind words. I actually worked pretty closely with Ryan Nock on the conversion material, and a lot of the ideas we discussed have since appeared in the EN5ider articles outlining the players guide and campaign guide info. It's worth noting that I started the campaign in Pathfinder and only flipped it to 5E at the start of Adventure 5. Because I was intent on selling the move to my players - I am very impressed with 5E and find it much easier to run, but my players were not necessarily gripped by the same compulsion - I had to make some choices I otherwise wouldn't have to get them excited about the change. I'm one of those people who has no qualm about reinterpreting a character with a new system and handwaving the differences in the spirit of fun, but consistency is a big deal to them. There seemed to be some cognitive dissonance over the continuity of characters who once had talents they no longer possessed.
Predictably, the Pathfinder party included some classes that didn't translate directly very well. I found it necessary to introduce an Alchemist and a Gunslinger that at least felt similar and had skills and abilities the players could get excited about. In both cases, I found a conversion someone had put together online and tweaked them a bit to meet my criteria. In retrospect, I wish I'd been able to get away with developing subclasses for each... I still don't know that I've seen a good Gunslinger subclass, but I've seen a couple Alchemists that are pretty interesting. Still would've been a big departure for that character, however. I also had a Witch in the party, but the player kinda fell in love with the 5e Warlock class and made the conversion easy on me. I did go ahead and convert a couple of spells that his character was fond of, as well as an Invocation or two. Finally, one of the PCs had the Unbreakable fighter archetype. Since he was one of the few who hadn't selected one of the Zeitgeist theme feats, I crafted a feat that helped mimic the feel of the Unbreakable concept.
I created a few other house rules just to help stylize some of the characters more. Again, I was going the extra mile to win my players' support. I built an Investigator rogue subclass for one of the PCs, and found an Artificer wizard subclass (I think it was in WotC's Unearthed Arcana articles) for one of the characters. The Alchemist was also a doctor by trade (he's the RHC medical examiner), and he also didn't take a theme feat. I think he'd found a Trait in the Pathfinder rules that gave him an appropriate bonus, and I made him a bonus feat that worked similarly.
The only other unusual conversion was a Deva character (which were called Aasimar in the Pathfinder version back when we started the campaign, so we still do). We use the write-up in the EN5ider conversion.
Probably the biggest adjustment for the PCs is the way wealth and magic items are handled. In the Pathfinder material, the characters received a specific stipend at regular intervals that they could use, among other things, to requisition magic items to keep their characters equipped appropriately. My players got used to this approach and also dove into the downtime rules in the Ultimate Campaign book, since the campaign is largely based in one city and they have weeks or months between adventures. The book includes an exhaustive system for investing money into building and starting businesses, and a couple of them used some of their stipend to do just that.
The economy in 5e is very different, as is the role of magic items in the game. The 5e Zeitgeist players guide states that "you’re assumed to receive a reasonable salary that covers 'comfortable' living expenses, but needs not be tracked in-game" and that "the Constabulary’s resources and connections let you requisition the tools you need for your missions." While this wasn't necessarily a problem - after all, the stipend in the Pathfinder version was generally provided above and beyond an assumed level of comfortable living - we were no longer dealing with actual numbers. A fairly robust breakdown of magic item distribution and requisition is offered in the Prestige section, but I found it important to tailor the options to my groups needs and expectations, as well as the kind of flavor I want in my game. I don't like to have a group swimming in magic items, for example, so it's common for most of the PCs (who are now 12th-level) to each have two or three permanent items - one of which might be pretty potent - and a small number of potions or scrolls. There are also one or two more potent items in the party's possession.
Fortunately, distribution tends to be pretty organic. That being said, I did introduce a "Q" type of character who has occasionally outfitted them with some cool gadgets and minor magical items. It's mostly just for fun, but the players love it.
The investment stuff we have to kinda handwave at this point, and wealth is fairly academic. I rely upon my players to make reasonable decisions about off-the-cuff expenses such as bribes and lodging and such. There have been a couple incidents where much larger investments were taken into consideration - one of the players had asked me about putting her own money into one of the railroad efforts in Adventure 6, for example - but we've had no difficulty navigating the situation to everyone's satisfaction.
For the actual adventures, I've been handling conversions on a week-to-week approach. I generally focus on converting encounters as faithfully as possible, with an eye toward the level of challenge they represent to the 5e party, and make sure I have plans for handling skill-based resolutions and more abstract scenarios appropriately. If you'd ever like to discuss specific elements of a given adventure, I'd be happy to review what I've done... or what I might have done, for adventures from before we converted over.
Sorry if I rambled a bit.