Lloris is a keeper so no, you can't really compare him with striker, and anyway he isn't better player than Welbeck, but from the lot you named he stands out as the only one who could be worth as Welbeck.
Verthonghen is average defender who makes mistakes quite often and wouldn't get into United side when everybody is fit(and Welbeck is better player than our defenders) and is yet to have good season in the premierleague, and was dropped for Vermaelen in Belgium team but for some unknown reason some people rate him. His pace maybe?
Eriksen, even though I quite like him, showed nothing to suggest he is better player than Welbeck yet. Good first season and that's about it, even if you compare them in things Welbeck is most criticised for - stats, last season their stats were pretty much identical, and Welbeck was dropped for van Persie and Rooney whenever they were fit even though he was much better performer than them at times last season, and still had more than decent stats, and his performances in big games are something else, while Eriksen turned out to be pretty much your first name on team sheet/was given opportunity and still didn't have better season than Welbeck. That doesn't mean he is poor player because he is exciting player but still his highest level is far from Welbeck's IMO, even Liverpool didn't want him for 12ish million pounds.
Right, here goes. Might as well, not that it'll do any good.
Erm, you said best
player. Obviously the two are not comparable, but Lloris is a better goalkeeper by some distance than Welbeck is a striker. He's the French Captain, one of the best goalkeepers in the league and well known throughout Europe. Of course he's better than Welbeck.
"Vertonghen is an average defender" - Stop right there, please. Vertonghen was considered one of Ajax's biggest talents, came to Spurs and in his first season in the Premier League was the best defender in the league and made the team of the season.
One poor season based on injuries and playing as left back and he's average? He's a very talented player who at his best is one of the best in the league. For some reason people rate him? He was bloody brilliant in his first season - both going forward and at the back. He probably wasn't far off Welbeck's best goalscoring season in the Prem whilst playing as a CB. He also wasn't "dropped" for Vermaelen for Belgium, he started against Argentina when they were knocked out and was pretty much regularly in the side. He played left back because they lack fullbacks, where he wasn't as effective.
Eriksen came in to this Spurs side at the worst side and was immediately our best player going forward, by an absolute mile, he did not just have a "good" first season, it was very good. Whilst Welbeck didn't always play - Eriksen also wasn't always in the side for a large portion of the season (He became one of the first names later on and suffered from injuries.) He was also played out of position often on the wing and was effective there
Eriksen had 7 goals and 9 assists. Welbeck had 9 goals and 2 assists. So no, they did not have "identical" stats. Eriksen had 2 less goals playing from an attacking midfielder position than Welbeck playing as a
striker or at worst a left-winger. He's not meant to pump out goals though, that isn't his job. His job as a CAM is to create and he created 7 more goals than Welbeck, for a team severely lacking in firepower. In his first season in this league, playing in a less advanced position. My arse did he not have a better season than Welbeck.
To compare his stats to other players in his position, David Silva had 1 more assist in a far better side going forward, Ozil had the same assists as him and the likes of Hazard had 7 assists. These sorts of players aren't strikers so aren't expected to produce crazy statistics and the fact they have similar tallies isn't anything to crow about. It's actually pretty damn poor that Welbeck has only 2 more goals than an attacking midfielder new to the league.