Working with incomplete datasets is common in planning influencer strategies, and while it may be challenging, it could be successfully navigated by:

1. Quality Over Quantity: It’s crucial to focus on the quality rather than the volume of the data. For instance, brands could prioritize influencers’ engagement rate over mere follower count.

2. Invest in Research: Brands could research and engage with potential influencers, gaining insights into their personalities, content styles, and audience demographics that may not be initially available in datasets.

3. Maximize Available Information: Brands could make the most of existing data, applying thorough analytics to understand engagement patterns, audience reactions and sentiment.

4. Experimentation: It’s beneficial to run smaller, exploratory campaigns to gather more data before investing in large-scale influencer campaigns.

5. Learn from Competitors: Brands could examine influencer tactics by competitors or other industries to gain insights.

Popular platforms like Hootsuite might be geared towards general social management, while specialist platforms like Flinque might offer advanced features dedicated for influencer marketing, including sophisticated discovery tools and detailed analytics. All platforms have unique strengths and the suitable choice would greatly depend on team needs and workflow.

Remember, investing in an influencer marketing platform could help solve data gaps by providing comprehensive data about influencers and their audiences. Regularly tracking campaign performance is also crucial as it helps iteratively improve marketing strategies and drive stronger ROI.