I think the full power kids being around Cell Juniors level is the last placement I had them. Seems somewhat close to the adults, but still noticeably below 18 in base, who should be << base Gohan and Vegeta. The way the kids defended from the Cell Juniors also remembers me a little the way Trunks was straining Vs them in the CGs. So having the kids around Trunks/Vegeta/Cell Juniors [CGs] placement doesn't seem so far off.
Last I checked, I had the base kids ~ SSJ Vegeta from the androids arc. I kinda looked into the fight closely and I think it's likely 18 was initially using a similar level of effort Vs Mighty Mask, which I call her resting base, as she was Vs Vegeta in their first switching of hands. Kid Trunks seems to have similar problems as Vegeta in fending her, so that's where I drew the conclusion more or less that base kid Trunks ~ SSJ Vegeta [androids arc]... When 18 said she'd go all out Vs Vegeta, she smiles before charging at him. When 18 sees the boys went SSJ, she smiles too, likewise, so I think she was about to go FP there much like she did Vs Vegeta, but once she realized their SSJs are that strong she just realized she couldn't do anything in a h2h battle.
SSJ Vegeta androids saga -- 340
Android 18 (holding back initially) -- 340
Android 18 -- 450
Base Vegeta [CGs] -- 330
SSJ Vegeta -- 3,300
Cell Juniors -- 3,500
Base kid Trunks -- 340
--- SSJ -- 3,400
Android 18 (Vs Trunks initially) -- 340
Android 18 (FP) -- 450
SSJ Trunks' blast -- 500
SSJ Trunks FP -- 3,400
[Trunks seemed to strain blocking her but she had the edge in the fight because of their mobility .. but still the fact her attacks drew in similar struggle from SSj Vegeta and kid Trunks that sounds good for me to keep former SSJ Vegeta and base kid Trunks on the same level, placing the SSj kids at the Juniors level more or less, and I also like to think Vegeta and Trunks in their CGs, more or less, reached their old SSJ levels with merely their base states... Making base Vegeta and Trunks [CGs] ~ SSJ androids arc, which always seemed to fit well for me and is cool when looking at both Vegeta and Trunks in terms of improvement, with their base level being already high enough that it could output the same level they had when fighting 18]
Base teen Gohan -- 500
--- SSj -- 5,000
Base Vegeta -- 625
--- SSj - 6,250
Base Goku -- 750
--- SSJ -- 7,500
Android 16 -- 750
Piccolo in the CGs I've somewhat close to Vegeta and Trunks. I think the artwork depicting him in a not so more severed shape is proof enough that he wasn't as distanced from them. Weaker sure, but still strong enough that he could hold his own against enemies slightly stronger than Vegeta without suffering bad injuries. If Vegeta is somewhat above 50% Goku's level, Piccolo may be in that vicinity of 50% MSSj Goku... So applying a 10x SSJ multiplier, Piccolo would just be way above any base Saiyans in the Boo saga.
Piccolo [CGs] - 2,700
Piccolo [Boo saga] - 3,000
Gohan and Vegeta's confidence in fighting in base in the ship indicates they're above 18. As for Piccolo, that's more debatable. Vegeta, for once, didn't see him there. So we don't know if he knows Piccolo is joining. Gohan, knowing Piccolo well, knows Piccolo isn't there to win... Piccolo seemed happy knowing Goku would be there and seemingly wanted an old match, switch of hands for old times sake. He knew he didn't have a chance against them, he was there to make his presence. So if he sees Gohan or the other Saiyans fighting in base, he'd know they'd be doing that to hide their identities. So it wouldn't be in character for Piccolo to quickly defeat them, he'd likely hold back to a similar level just so he can have his old fight again for old time's sake. Gohan likely knows that based on Piccolo's mentality... So he doesn't see that as a danger. As for 18, he knows she's there to gather as much money as she can... So he knows she wouldn't lose the opportunity to defeat their bases if she could. So Gohan needs to be decently above 18 at least I'd say.
Kaioshin is way above Piccolo. The EML has him in CGs Goku's level. Since I've Gohan ~ CGs Goku under same forms, I prefer to keep Kaioshin a little bit below that since I think he's below all SSJ except kids. So 4,500 for him would do it, as that's a very big gap over Piccolo (4,500 Vs 3,000), tho the Shin Vs Piccolo debate may still be up for me, but going now for simplicity's sake.
Kaioshin -- 4,500
Pui Pui is trash, but to at least give him some credit, maybe he can be on Freeza's former level. That'd be 140 in the scaling above.
Yakkon is on par with base Goku. He threatens Goku at first, then Goku kicks him in the dark and Gohan thinks he should lend Goku a hand since he's fighting an enemy ~ his power and Goku would need to use his other senses which could handicap him a little.
Yakon -- 750
That just happens to be where I've placed 16 too, so the strongest base Saiyan is on par with 16 to me, and Yakon is a 16's level foe to me.
That's it. My breakdown of the whole situation. That part is a mess, I think that's the absolute best I could do with it.
While most would like to have the kids close to Gohan, I think keeping them relative to the Cell Juniors is enough to impress both Gohan and Vegeta and make them worry since they have such strength at such a young age. I think their first sparring with Goten forcing Gohan to fly may be indicative they're close, very close, but I think it's possible Gohan wasn't all reveled up, was more on a high level already, but not using his best possible available power, moreso testing Goten a little. Vegeta also made a case to test Trunks and had more problems than he had Vs Zarbon dodging his attacks and we sure as heck don't think Kid Trunks is closer to Vegeta than Zarbon was to Vegeta, right? That'd make Trunks 92% or so of Vegeta, so I sure think in both sparring sessions there was a little of a wiggle room to argue the unexpectedness of their strength caught the adults (or teens in Gohan's case) off guard and it'd be different were it an all out battle.
Still tho, I like to place them above Piccolo as Piccolo didn't make a case to stop Trunks when he went to save Vegeta from Boo and he didn't try it either with Goten knowing they'd be going to their deaths and adding to Vegeta's soul as he stated. So I think he couldn't stop them. Plus, he was pushed back when Goten and Trunks powered up in the lookout, which may not mean much, but since he had already knowledge of their strength, I think him being pushed back didn't come merely from a "being surprised position' but being weaker, intimidated by their powers. He also states Goten and Trunks are the only hope for Earth, as tiny as they might be and while that isn't conclusive enough as it may be moreso talking about their potential when using the RoSaT, I think adding all this together ads to the kids being > Piccolo as a minimum threshold placement.