Basically akin to the multiple Fokkers, ATRs and CASA MPAs around the world.
Yeah, it's getting to be a crowded field ... even just for Q400-based systems. That PAL concept goes back to at least 2015 (with both MPA and coast guard proposals being made). In the past, Field Aviation proposed a Q400 derivative for Canada's FWSAR contest - complete with long-range pannier tanks, MAD stinger, belly radar, refuelling probe, etc. Field later put forward its P400 concept (IAI/Elta EL/I-3360 and EL/M-2022 platform ... although there were other sensor suite options).
Cascade Aerospace does Q400 cargo and air tanker conversions but were also involved with L-3's Q400 MPA program. The first L-3 Mission Integration Division Q400 proposal was an unsolicited MRA offering to the UK as a
Nimrod MR.4A program replacement. For that, L-3 was joined by Marshall Aerospace and Defence, Cascade, Selex ES, and Ultra Electronics (the latter two supplying
Seaspray 7500 search as well as
Eagle wide-angle radar and sonobuoys, respectively). L-3's Multi-Mission Q400 with optional belly 'canoe' sensor fairing followed.