Every time spec ops rolls around, the wiki, the forum, and various FB groups get flooded with "Who should I recruit?" and "Do I spend gold?" questions. These issues and concerns can seem earth-shattering, but really can be broken down quite simply.
The answer, every time, lies in priorities. The objective of the special operation is to acquire the character while expending as few resources as possible. Since gold is the rarest resource in the game and you need to try to avoid spending it unnecessarily, you should farm CP until the last day of the spec ops and if you haven't been able to assemble the required characters by then, you spend your gold. This is the one strategy that both meets your top priority (get the character) and preserves your resources (avoid spending gold if possible).
So then, the only question left is who to recruit first. You want to get the strongest hero first and the weakest hero last so that if you fall short using CPs, you at least recruited good characters.
^ the above is fact ^
v the below is opinion v
In the current spec ops (22), I recommend acquiring the mandatory deploy characters in the following order:
1. Nico Minoru - She's an all-star, with more trickery at her disposal than a barrel of Lokis. From resurrection to giving extra turns to taking extra turns to applying debuffs to maximizing those magic-friendly EISOs and AISOs, she has a lot of ways to make a lot of good things happen.
2. Gorgon - Free Rising Up is his best attribute, but not his only one, as his multiple ground attacks will bypass protect actions, and he sports an AoE default for follow-ups or counters. That said, his best skill has all the drawback of Havok's without all the damage or turn sequence speed, and his other abilities are hardly game-changing.
3. Medusa - Infiltrators are already behind the 8 ball because you try to take them into PvP and Quicksilver eats them for lunch like so much free pizza. Medusa is no exception, and she just doesn't have the active turns to compensate for her inherent class disadvantages. The queen of the Inhumans is almost as disappointing as the king is.
All right, now you know, and knowing is half the battle. The other half is doing it, so get to work!