I wanted a character who would do everything (no swapping out characters for certain tasks). So I made a Noble Githyanki Ranger (Gloomstalker). At 1st Level, I had Athletics, Sleight of Hand, Stealth, History, Investigation, Nature, all WIS Skills (Githyanki), Persuasion. This was *almost* good enough but I took Actor at 4th Level to pick up Expertise in Deception and (though it doesn't matter really) Performance. I will get Arcana at 6th Level Gloomstalker and (assuming I don't Rogue multiclass) Religion at 10th. So, at that point, I'll be missing Acrobatics and Intimidation. (I'm more likely to multiclass into Rogue at 9th Level, though, and pick up Acrobatics instead of Religion.) You might think it would have been better to start as a Rogue to get one more Skill Proficiency than starting as a Ranger, but Iron Will doesn't stack with a Rogue's initial proficiencies (DEX and INT) and, less importantly, you would get slightly fewer hp.
Rangers (and Rogues) really only need DEX to be pretty effective, so I started with 17 DEX, got the +1 to any Attribute that I'm keeping vague to avoid spoilers to bump to 18, and can get to 20 at 8th Level.
Because I was going for skill monkey, I thought 12 CON was sufficient; my Rogue only had 14 CON and fewer hp per Level and never had much hp trouble, so it seems fine and has been so far, even when I tank.
WIS is sometimes useful, particularly for Rangers, though I've not found it to be of overwhelming importance. Good enough to merit a 14 WIS, though, because I may as well put a 14 in something.
I knew I was going to take Actor, so wanted to start with an odd CHA, and 13 seemed about right (to 14 at 4th Level).
And I still had enough left over for a 12 STR after dumping INT.
I walk around with the Warped Headband of INT in my pocket and put it on before interacting with people or things, which is a little fiddly, but I've got better things to wear in combat. And I carry around that thievery ring for traps and stealing. With Guidance, 99.75% disarm most traps. I rarely fail on social tests with great Deception and a good Persuasion backup.
Another thing to consider with your front man: Rangers get the two most common saves, STR and DEX, and good hp. Gloomstalkers pick up INT and WIS saves at 7th Level, too, which is a better save situation than for any other class. Plus spells. So not just a skill monkey; also the best fighter in the group, at least during Round 1, unless you optimize the origin characters, very stealthy, and pretty durable.
I found it hard to do better with a Knowledge Cleric, even a Githyanki one, because you tend to have to use Astral Knowledge for DEX (only 3 skills), Soldier for Athletics, and you will have proficiencies in WIS- and CHA-based skills and Expertise in some INT-based skills (and another INT-based proficiency generally due to the lack of Cleric proficiency options), so getting all proficiencies for an attribute really just gets you a few each time. (A Ranger Githyanki can pick up almost as many with just Astral Knowledge (WIS)). Plus Expertise in INT-based skills is pretty situational, Clerics don't multiclass particularly well, and Githyanki Clerics need STR for their decent weapons, so your weapon options are suboptimal because you can't afford to get STR to 20.
The Bard's Jack-of-all-Trades is also pretty unimpressive compared to a Ranger Githyanki; that +1 bonus (eventually +2) to all skills in which you don't have proficiency is underwhelming. I didn't enjoy my Bard playthrough (with the same goal of having one character lead in all situations). Bards frequently have great spells but they are fairly one-note (ha ha). They seem to do everything just a little worse than what some other class can do, like Sorcerer or Wizard for spellcasting and several other classes for melee or ranged combat; for the latter, you need a character that can afford to take STR or DEX all the way up (or a Warlock who can use CHA with their weapon).
