Assuredly not an expert here, but am currently going through gear selection so will give you what I've found. I am not extraordinarily serious about the competitive side so this may not be the optimum gamer gear. Some of the gear is linked, it doesn't really stand out on the forum for me but hover over and you should find some links.
From what I understand (you may know this) the big gear differences are going to be:
USPSA will allow a 2-piece inner/outer belt, IDPA is going to make you thread the belt with your stuff attached through belt loops.
USPSA allows drop/offset holster (rules may vary by division but I believe a common one is that the butt of the gun needs to be at or above the top of the belt, and there are offset rules) where IDPA doesn't allow drop/offset. Someone with a lot more experience can post the specifics or they can probably be found by searching "USPSA offset" or similar.
So basically you're looking at two sets of gear. See the difference between the USPSA and IDPA kits on the benstoegerproshop page, linked below.
USPSA: 2-piece belt and BOSS DOH holster hanger
IDPA 1-piece belt and no DOH hanger
Long story short I don't think you can go wrong with the gear in either of those benstoegerproshop.com kits, but you will need to roll up your sleeves to get things set up for your Roland.
For USPSA the gear in that kit is what I see recommended to newer shooters, though depending on division that may be too many mag pouches for you. I own that DAA belt, no major complaints. I own the BOSS DOH hanger and if you can get it configured like you need to (see below) it is a great piece of kit and locked down and very stiff with that belt. The BOSS hanger has different Y-plates for each hole pattern (Blade Tech vs. Safariland). Chose to go with different mag pouches but without a strong reason to recommend someone else do the same.
For your weapons with lights and/or compensators, you are going to need to do some experimenting with available holsters and attachment hardware, I can help you offline because there are too many combinations to cover. It all comes down to laying out a bunch of stuff that may include adapters with various length hardware, spacers, and belt attachments and just experimenting, unfortunately. There are probably more (and better) options out there but Safariland and TRex Arms are probably where I'd start looking for OWB light-bearing that can handle a compensator. The
TRex Arms Ragnarok has the advantage of having a hole pattern that can be attached to the Blade-Tech or Safariland hole pattern (for your hanger or belt attachment piece). The disadvantage is that I believe P&S collectively takes a dim view of the company, some of its products, and proprietor, but I'll leave you to sort that out in your priority list.
Aside from the BOSS hanger, all my stuff (pouches and dump pouch) is on
Blade Tech Tek-Loks, which work OK for the 1.5" thick outer DAA belt. Specific competition mag pouches like the Ghost ones are going to fit better but they do screw on and off.
I'm at sort of a midway point where I want a 2-piece 2" belt and all Tek-Loks (like the
Stormrider Competition Overlord) but I haven't found a holster attachment I like as much as the BOSS, and the BOSS is specifically set up for the 1.5" belt. I've seen people have success with the Safariland Mid Drop Belt Loop (which accommodates a 2" belt) and a thigh strap for training/ninja stuff but don't think that flies in USPSA. My next experiment to handle both USPSA and generic training is going to be to try to hang the BOSS hanger from a Tek-Lok but up until a few weeks ago the Stormrider Gear was out of stock so it hasn't been a priority for me. I have also done some experimentation with sticking a
Safariland QLS receiver and fork in between the belt attachment and holsters to be able to pop different holsters on your rig, but that's getting away from competition-focused.