What do you want this gear to accomplish? And what’s your budget? Good gear gets expensive. Overall Molle gear is very flexible in the type and location of the pouches and is a big step up from the Alice system.
If you’re looking for function over trying to recreate a specific historical setup, I wouldn’t touch a FLC. There’s a reason why everybody who has an option either wears a plate carrier or a chest rig.
A plate carrier (like the IOTV) is going to give you the ability to carry armor. Some will have provisions for only plates, while others will have a larger pocket that allows you to include soft armor as well. Adding soft armor gives you a larger coverage area, often including your sides, but that usually only gives you pistol/frag protection for that area (as opposed to rifle protection from the plate). This is one of those areas where your threat profile dictates what you choose. A carrier with both hard and soft armor will give you better protection than a carrier that has just a plate, but it will also be heavier and hotter.
A chest rig gives you less space for pouches and gear and generally doesn’t have provisions for armor, but it is usually a decent bit lighter and allows you to stay a lot cooler while carrying all the gear (open back and less on the front gives you more airflow). A PC will generally support more weight than a chest rig, but that’s not always a good thing. Sometimes less weight is better. You can also put a plate carrier over a slick (no pouches) PC. For what it’s worth, I greatly prefer a Rhodesian style Molle chest rig.
Honestly if you want to go with a plate carrier, I think you’d get a better result getting commercial gear rather than a military surplus. There’s LOTS of cheap stuff out there that won’t last, so make sure you get a plate carrier/chest rig from a good company. General rule of thumb - if it’s on Amazon or eBay, it’s probably cheap crap that won’t hold up to serious use. There are exceptions, but if you want to use the gear, buy it from a reputable source.
I have seen some good surplus chest rigs out there. Eagle makes a good Rhodesian style Molle chest rig, and there are some Tactical Assault Panels that are a good low cost (and low feature) chest rig. The TAP can also be attached to a plate carrier with the right buckles, so it can technically serve two purposes.
https://www.venturesurplus.com/products/army-multicam-tactical-assault-panel/
Pouches are a great thing to get as surplus, and it saves a lot of money. Buy more pouches than you expect to need. As you try different things, you’ll be glad to have extras as opposed to having to decide you want to make a change then place another order. I’ve lost count of how many times I’ve pulled off a pouch and put it in the bin and then later decided that pouch would be perfect for some other use.
One trick I’ve learned is to look at how knowledgable people have their rigs set up and note the similarities and differences. My gear has gone through many different revisions based on my experience and priorities changing, so just expect to swap things around once in a while.
As a general rule of thumb, medical, TQ, and 3-4 mags will get you a decent baseline setup. Don’t put anything on your back - keep everything where you can reach it. If you plan on fighting standing up (raids, working from vehicles, that sort of thing) doubled up mag pouches can be useful. If you plan on fighting from the prone, single mag pouches on your chest let you get closer to the ground (and spreads out the weight a bit more).
I feel like I’ve talked a lot about PC’s and chest rigs…
Belts - you can use an Alice belt with Molle pouches, but things will move around. I used some high test fishing line to keep pouches roughly in place, but I eventually moved to a battle belt with Molle loops. There are some Air Force battle belts out there right now for cheap that use the Alice belt (that specific battle belt has a sleeve for the Alice belt to actually be used to secure everything) so you might be able to reuse your holster while also having Molle for the pouches.
Packs - avoid the army’s Molle ruck sack. Everything I’ve heard about it is that it’s very uncomfortable. The USMC FILBE is a decent pack, but it is massive and heavy. My pack (empty) is 10 lbs (more than double my commercial pack of a similar size). Also keep in mind that it is designed to be worn while you’re also wearing a plate carrier. It is still definitely useable without a plate carrier, but it is not going to be as comfortable as a commercial pack. The USMC ILBE pack was made by a commercial manufacturer and is reportedly very comfortable as a pack, but doesn’t fit very well if you’re wearing armor.
The FILBE also has an assault pack that connects to the main ruck, and the assault pack itself is a pretty decent day pack.
Another thing - there’s nothing wrong with an Alice pack, but the FILBE frame is Alice compatible and allows you to use the Alice pack with the (much more comfortable) FILBE and/or Molle straps and hip belt (you can buy the parts individually).
Cost wise, right now an ILBE is probably around $200-$250, a FILBE is around $100-150, and last time I priced setting up an Alice pack with the FILBE gear it was about $60-75 (without the actual pack). Also consider that the ILBE is in woodland Marpat while the FILBE is coyote. The FILBE doesn’t stand out quite as much as a “military” pack if you’re hiking with it.
My general thought is that the FILBE assault pack is a decent buy, but unless you need the specific advantages of a military ruck (LOTS of space, NIR compliant if you’re using night vision, or need something that works while you’re wearing armor) a commercial pack will serve you better than a military pack. That said, if you’re on a budget the military packs definitely work.
