A clause stating that taxes can be levied is essential, as other governments throughout history have tried to leave that out and it led to a very swift end for those governments. Ultimately any tax right now would not be practical or reasonable, but basic taxes for those who do eventually choose to live in Asgardia will be inevitable. There should be a goal to limit taxes as much as possible, and supplementing them with other sources of income would be ideal, but the government will have expenses and will need resources to manage those expenses. It will be on the members of parliament to not over reach, and it will be important for us as citizens to elect officials that won't add unnecessary burden to the populous. That being said, an y tax levied right now would be met with laughter and eye rolls. If an amendment were to be proposed It would be better to specify that taxes can only be levied on those residing within Asgardia, meaning no tax before the station is built.
Right now before parliament is formed is the time to begin discussion on what we think taxes should and should not look like, as that discussion will influence parliament once it is formed. For those interested in being part of that, I started a forum post in the policy and scope section of the ministry of finance. Tax or no tax, it is a discussion that needs to be had and decided on one way or the other before inviting investors.