Leisure Stroll for Saber Lancelot?

If you dont want to level him 2nd skill, then using Leisure Stroll is not a bad idea.
But it is just not "flexible" Arts team. A Art critical team will build around him, but sometimes Art supports also need critical stars since critical Art card can boost their NP gain to 200% then they can release NP faster.
Saberlot's 2nd skill in the cool-down period is good for him not "over-adsorbing" stars. Using Leisure Stroll or other star adsorption CE is somehow narrowed your team's direction (only focusing on Saberlot's critical damaging, even though he has only 1 Quick card in RNG round but 16-25 stars). Comparably so far it is not a bad idea since Saberlot can slash out almost every boss in his Critical Brave chain or NP spam in 1-2 turn, but later on facing multi-hp bar or buff-debuff bosses, it is also recommend for your Art supports' critical Art cards and Art chain for a better tendency of team NP spam , in order to reducing charge, team defense up and healing, etc.

For Saberlot and from the CEs you currently have, I think you'll benefit more with MLB Hot Springs. The 4 Crit Stars per turn really does come in handy and the extra crit damage will go a long way with it. As long as you aren't pairing Saberlot with another servant with high star absorption you might actually crit more with the extra 4 stars that are guaranteed than generating stars on cooldown.

Basically every CE that you mentioned is pretty viable for Sabrolot, so it's kind of a wash (with some options being a bit better in certain situations or with certain comps). I'd probably lean toward Hot Springs once you max his 2nd skill, but I dunno for sure. Probably no need to worry about it too hard, since we have to use event CEs like 90% of the time anyway.