That would work. I typically stay away from effect expiry. I think that it is too powerful and tends to have characters sidestep stories rather than engage them. Doing what would otherwise be ten seasons worth of work in a single season combined with bonuses from the lab schedule rules tends to allow any magus to make a significant item in any art combination. That's a dynamic that I don't enjoy. Yet they certainly are rules as written and as long as I'm writing two versions of effects, one rules as I think they should be and one rules as written, there's no reason not to use them in the second.
So for the rules as I wish them to be version Ranulf will spend his time as above, spending one season on Command of the Lion and one on the Collar of Obedience. In the Rules as written version, Ranulf does not invent Command of the Lion he spends one season opening a collar for enchantment and one season enchanting a single effect in it:
Without Command of the Lion to use for a similar spells bonus his rego animal lab score is 65, so he beats the effect level by 16. If his enchantment is designed to expire in seven years (*5 speed multiplier) he can create it in a single season.
With the "rules as written" version he can not use his fixed Arcane connection to call the beast to him using Rego Animal but he could use the connection to open an intangible tunnel, then Revoke the protection of Magic to remove the creature's MR, then even with his intellego deficiency he'd be able to spont a range touch duration momentary "where is this creature?" spell at level 4 and fly back up on a cloud boat and capture it a second time. He'd then slap on the collar and activate it.
With the "Mentem equivalent Animal spells do not need to take in to account the target creature's size" version. Ranulf uses his fixed arcane connection to cast Command of the Lion on the Sky Drake and have it land near his covenant and obligingly allow the Collar of Obedience to be placed upon it.
In either case he'd then present Obrect's sky drake to the Tremere Arch Maga. Giving her use use of the Scepter of Beastial Communication, the Collar of Obedience, and Olbrecht's Sky Drake itself to use for at least a year. He'd like the two enchanted devices back eventually, but he'd provide one of the fixed arcane connections along with the symbolic representation that he likes better (let's say the painting) to the arch maga as a gift for her to keep (the other fixed AC and the sculpture he keeps for himself).
To some extent the devices that he gives the arch maga to control the drake are irrelevant. I realize now that I've set up the character as someone who is an arch maga, whose primary field of study is magical spirits and creatures, and who now has a fixed arcane connection and a sympathetic connection to the sky drake. I think it rather unlikely that she needs Ranulf's enchanted devices at all. In his future years Ranulf would, if he had the time, always send the Arch maga a letter by redcap if he intended to use the drake for any reason. He'd do this to make certain that he was not interfering with her use of the beast, it doesn't matter how powerful you are, it doesn't make sense to upset an arch maga.
Do you think Ranulf would be a more interesting NPC if his plan works and he's an archmagus, or would he be better if something goes awry and he's not?